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Lipid Oxidation and Quality
LOQ 1: A Re-examination of the Antioxidant "Polar Paradox" Paradigm
Chair(s): A. Richards, CSIRO, Food and Nutritional Sciences, Australia; E. Decker, University of Massachusetts, USA; and P. Villeneuve, CIRAF, France
The Many Facets of How Antioxidants can Impact Lipid Oxidation Reactions in Foods. E.A. Decker, University of Massachusetts, Amherst, Amherst, MA, USA
It is extremely difficult to predict when an antioxidant will be effective in different food products meaning that taking a rational approach to developing effective antioxidants systems is challenging. Numerous compounds can inhibit lipid oxidation by a variety of mechanisms including metal chelation, free radical scavenging and singlet oxygen quenching. The effectiveness of an antioxidant is dependent on factors such as metal binding constants, redox potential, antioxidant radical stability and solubility. For example, chelators can inhibit metal-promoted lipid oxidation by preventing redox cycling and inhibiting metal-lipid interactions but can increase prooxidant activity by increasing metal solubility. Likewise, free radical scavengers can inhibit lipid oxidation by producing low energy free radical but can promote lipid oxidation when their redox potential is high enough to reduce metals into their more prooxidative states. The oxidative stability of a food is also dependent on interaction between antioxidants as one free radical scavengers can regenerate another. Since antioxidants have such a broad array of pathways in which they can impact oxidative reactions, it is not surprising that their ability to prevent lipid oxidation in foods is difficult to predict.
Effect of Emulsifier and Related Factors on the Antioxidant Activity in Emulsion. Naoko Kimura, Goki Azuma, Masashi Hosokawa, Kazuo Miyashita, Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
Membranes surrounding the emulsion droplets consist of lipids, water, and surface-active substances such as emulsifiers and proteins. They provide a protective barrier to the penetration and diffusion of metals or radicals that initiate lipid oxidation. The different behavior of antioxidants in or out of the interface has been also reported; that is called polar paradox. On the other hand, it is true that emulsions are complex, multi-component, and heterogeneous systems, in which lipids are present with various types of other components in aqueous medium. To understand the true significance of antioxidants on lipid oxidation in an emulsion, we should pay much attention to other factors such as substrate (degree of unsaturation), emulsifier, particle size et al. When the stability of ethyl linoleate (LA) and ethyl DHA (DHA) were compared in oil in water emulsion with tocopherol and trolox, trolox showed the higher antioxidant activity on DHA than LA. This is due to the difference in polarity of LA and DHA. Emulsifier also showed a strong impact on the effect of different kinds of antioxidants. The activity of antioxidant was affected by the interaction with emulsifier.
Evaluation of the Polar Paradox Based on Antioxidant Functionality in Various Food Systems. R. Nahas, Kalsec USA, Kalamazoo, MI, USA
The concept of "Polar Paradox" has been useful in explaining several observations regarding functionality of polar antioxidants in non-polar systems, and less polar antioxidants in polar systems. Several cases however, contradict the concept. Experimental data on lipid oxidation, using natural, plant extract antioxidants in comparison to pure antioxidant standards revealed a large correlation between the mode of action of antioxidants and their corresponding efficacy in certain food systems, but not necessarily according to their polarity. Hence, the conclusions might present a more generalized view on the applicability of the polar paradox in complex food systems.
Phenolics and Lipophilized Phenolics as Antioxidants in Fish Oil Enriched Emulsions. A.-D.M. Sørensen, N.S. Nielsen, C. Jacobsen, Technical University of Denmark, National Food Institute (DTU Food), Denmark
Emulsions containing omega-3 LC PUFA are highly susceptible to oxidation. This causes formation of undesirable flavors and loss of health beneficial fatty acids. Many omega-3 enriched food products on the market are oil-in-water emulsions. According to the so called "polar paradox", polar compounds work better as antioxidants in bulk oil, whereas lipophilic compounds are better antioxidants in emulsions.This presentation is an overview of our previous work in the area of fish oil enriched emulsions with antioxidants. Our studies have shown that the lipophilicity of the compounds is not the only factor determining their efficacy as antioxidants in simple model systems. Interactions between the antioxidants, emulsifier and pH also influence the antioxidant behavior. Moreover, studies with lipophilized phenolics in a food emulsion showed that there is no linear increase of antioxidant activity with increased lipophilicity. Instead a cut-off effect was observed in relation to the alkyl chain length lipophilized to the phenolic compound. Furthermore, the efficacy of lipophilic antioxidants is influenced by the type of food system. Thus, our results show that the antioxidant behavior may not be as simple as stated by the "polar paradox" hypothesis. According to our research results in this area, this hypothesis deserves reconsideration.
Hydroxytyrosol Fatty Acid Esters as Relevant Surfactants: a Potential Explanation for the Nonlinear Antioxidant Activity found in Oil-in-Water Emulsions. Ricardo Lucas1, Francesc Comelles2, Salomé Lois3, David Alcántara1, Olivia Maldonado1, Melanie Curcuroze1, Jose Luis Parra2, Isabel Medina3, Juan Carlos Morales1, 1Instituto de Investigaciones Químicas, CSIC – Universidad de Sevilla, Sevilla, Spain , 2Institut de Química Avançada de Catalunya, CSIC, Barcelona, Spain, 3Instituto de Investigaciones Marinas, CSIC, Vigo, Spain
Several groups have found results with different lipophilic phenolic antioxidants that disagree with the polar paradox paradigm. We observed a nonlinear tendency in antioxidant capacity of hydroxytyrosol fatty acid esters (HTFA) in fish oil-in-water emulsions, with a maximum for hydroxytyrosol octanoate. It has been postulated that an important factor in explaining this behaviour maybe the physical location of the antioxidants in an oil-water interface. We prepared a series of HTFA with different chain length and studied their surface active properties in water since these parameters could be related to the preferential placement at the interface. We found that HTFA are remarkable surfactants when the right hydrophilic-lipophilic balance is attained and as efficient as emulsifiers commonly used in industry, such as Brij 30® or Tween 20®. Furthermore, a nonlinear dependence of surfactant effectiveness is observed with the increase in chain length of the lipophilic antioxidants. This tendency seems to fit quite well with the reported antioxidant activity in emulsions for HTFA. This potential explanation of the nonlinear hypothesis will help in the rational design of antioxidants for oil-in-water emulsions.
Cut Off Effect of Phenolipids in Emulsified, Cellular or Microbiological Systems. C. Bayrasy1, M. Laguerre1, C. Wrutniak-Cabello2, J. Lecomte1, J. Weiss3, S. Suriyarak3, B. Chabi2, G. Cabello2, E.A. Decker4, P. Villeneuve1, 1CIRAD UMR IATE, Montpellier, France, 2INRA UMR DCC, Montpellier, France, 3University of Hohenheim, Stuttgart, Germany, 4University of Massachusetts, Food Science Dept, Amherst, PA, USA
It is generally admitted in drug research that antioxidant capacity increases with lipophilicity and that the most lipophilic compounds will have the highest activity. Using emulsified and cellular systems, we have recently demonstrated that this concept is false, and that highly lipophilic compounds display an unexpected low antioxidant capacity. Specifically, we have reported in oil-in-water emulsion and in human dermal fibroblasts, that antioxidant capacity of a homologous series increases as the alkyl chain is lengthened, with a threshold for a medium chain, after which further chain extension leads to a drastic decrease in antioxidant capacity. This nonlinear or parabolic relationship between hydrophobicity and antioxidant capacity is termed as "cutoff effect" and has been observed with two complete homologous series (chlorogenate and rosmarinate esters). Surprisingly, we have also demonstrated that the same nonlinear phenomenon dictates the antimicrobial activity of chlorogenate and rosmarinate esters. Accordingly, the best antioxidants (dodecyl chlorogenate/octyl rosmarinate) are also the best antimicrobials.Taken together, these results suggest that the cut-off effect may dictate both antioxidant, antimicrobial, and emulsifying effectiveness of phenolics and phenolipids in heterogeneous systems involving lipids as emulsified droplets, or membrane.
LOQ 1.1: Lipid Oxidation Challenges and Potential Solutions in Food Systems I
Chair(s): X. Pan, Solae LLC, USA; and U. Nienaber, Kraft Foods Inc., USA
Model Emulsions as a Tool for Studying Antioxidant or Prooxidant Activities of Foods and Food Ingredients. C. Genot1, A. Meynier1, C. Dufour2, M Viau1, L. Ribourg1, O. Dangles2, 1INRA UR1268 Biopolymers Interactions Assemblies, Nantes, France, 2INRA, University of Avignon, UMR408 Safety and Quality of Plant Products, Avignon, France
According to food safety agencies, it is of utmost importance that Western consumers readjust their lipid intake and that consumers opt for polyunsaturated fats. However, these fats are prone to oxidation during technological operations and during digestion. The resulting lipid oxidation products led to the development of off-flavours that decrease the acceptability of the products. They also could contribute to the development of several pathologies such as cardiovascular disease and colon cancer. It is therefore of interest to be able to predict development of oxidation in complex food formulations. Model emulsions were developed to assess the susceptibity to oxidation of milk fat as modulated by its composition and several formulation parameters, the pro-oxidant activity of foods or food components or the antioxidant efficiency of phenolic compounds in conditions that mimic the physico-chemical environment of lipids under gastric conditions.
Effect of Plant-derived Extracts on Oxidative Stability of Food Emulsions. S.P. Janaka Namal Senanayake, Jerry Erdmann, Cathy Dorko, Danisco USA Inc., New Century, KS, USA
Oxidation of lipids in food emulsions is a serious concern since oxidation produces undesirable flavors and aromas. Lipid oxidation may also negatively affect the nutritional quality of food products. The large surface areas of droplets in the non-continuous phase of food emulsions present particular oxidative challenges to food manufacturers. Although synthetic antioxidants have been widely used in food emulsions to inhibit lipid oxidation, the trend is to decrease their use because of the growing consumer concerns over the use of such chemical additives. Consequently, the search for natural additives, especially of plant origin, has notably increased in recent years. Plant-derived extracts, such as rosemary extract, green tea extract and natural mixed tocopherols may be as effective as synthetic antioxidants in various food emulsions. This study presents results from different food emulsions containing plant-derived extracts. Models chosen for experimentation were salad dressings and mayonnaise representing oil-in-water emulsions, and margarines and spreads representing water-in-oil emulsions. The efficacy of natural additives, such as rosemary extract, green tea extract and natural mixed tocopherols in food emulsions will be evaluated.
Antioxidant Activity of Fish Protein Hydrolysates in in vitro Assays and in Oil-in-Water Emulsions. K.H. Sabeena Farvin, Lisa Lystbæk Andersen, Charlotte Jacobsen, Henrick Hauch Nielsen, Flemming Jessen, Section for Seafood Research,National Food Institute (DTU-Food),Technical University of Denmark,, B. 221, Søltofts Plads, DK-2800 Kgs, Lyngby, Copenhagen, Denmark
The aim of this study was to screen different protein hydrolysates with respect to their antioxidative properties in order to select the most promising extracts for further evaluation in oil-in-water emulsions. Three fractions of protein hydrolysates (Crude, >5kDa and <5kDa) from cod and plaice were screened for antioxidant activity by using four in vitro assays viz, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, reducing power, ferrous iron-chelating and inhibition of lipid oxidation in liposome model system. Cod protein hydrolysates exhibited significantly higher antioxidative effect in various antioxidant assays and were selected for further study. The lower fraction <5kDa was further fractionated by using a 3kDa cut-off membrane to get two fractions 3-5kDa and <3kDa. Thus, four fractions of cod protein hydrolysates (Crude, >5kDa, 3-5kDa and <3kDa) were further screened by using the above mentioned antioxidant assays. Interestingly, it was found that the fraction <3kDa showed very good reducing power, Fe2+ chelating activity and DPPH radical scavenging activity. Moreover, the 3-5kDa fraction was very effective in retarding lipid oxidation in liposome model system. These fractions were therefore selected for further evaluation in 5% fish oil in water emulsions.
Antioxidative Properties of Ergothioneine in the Fruiting Body and Spent Culture Medium of Flammulina velutipes: Application to Fish Aquaculture. Toshiaki Ohshima, Huynh Bao, Tokyo University of Marine Science and Technology, Tokyo, Japan
Effects of feeding the extract prepared from the fruiting body and spent culture medium of Flammulina velutipesasas a supplement on color stability and lipid oxidation of the dark muscle of yellowtail fish Seriola quinqueladiata rich in myoglobin during postharvest storage of the dark muscle were evaluated. The fish of control group was fed on commercial diet on every other day for 1 week after beginning of feeding. The fish of 1% and 10% groups were fed on 5 g of the commercial diet containing 1% and 10% of the extract solution (= 0.36 g and 3.6 g of the extract dry materials per 100 g of diet, respectively), respectively, on every other day. After 4 weeks of feeding, the fish were starved for 5 days without any feeding. There was no mortality during the feeding period for 4 weeks and the fish grew normally. Browning development in dark muscle of the yellowtail fed with 1% and 10% of the extract in diet was remarkably suppressed during 4 days of storage at 0-2°C. These results clearly showed that the extract is a promising source of natural antioxidant which can be used for aquaculture to improve quality of fish meat during post-harvest storage at lower temperature.
Influence of Cultivar on Antioxidant Profile and Content in Olive Leaves. M. Syrpas1,3, V. Van Hoed1, C. Van Poucke2, S. De Saeger 2, A. Kiritsakis3, R. Verhé1, 1Ghent University, Faculty of Bioscience Engineering, Department of Sustainable Organic Chemistry and Technology, Ghent, Belgium, 2Ghent University, Faculty of Pharmaceutical Sciences, Ghent, Belgium, 3Technological Educational Institution (TEI) of Thessaloniki, Tessaloniki, Greece
Olive leaves are considered to be a rich source of phenolic compounds known for their multifunctional bioactive properties. The concentration of phenolic compounds is subject to the influence of many factors, such as cultivar, environment and phenological stage during sampling. The purpose of this research was to analyze and compare the phenolic compounds in olive leaves of twenty one different cultivars. All the samples were harvested at the same time from the same orchard and were grown under the same cultivation treatment and climatic conditions. Olive leaves were characterized by the presence of phenolic acids like ferulic acid or salicylic acid, phenolic alcohols like tyrosol, flavonoids and their glycosylated forms and secoiridoids (typical group of the Olea family). Oleuropein (usually the main component reported) was not always the main constituent of olive leaves. The various cultivars did not exhibit significant differences in the composition of their phenolic profile but differences were noted in the level of phenolic compounds. Antioxidant activity was correlated with the free radical scavenging ability of the various cultivars. Moreover, the stability of two edible oils was increased by adding phenolic extract of the olive leaves.
LOQ 2: Lipid Oxidation Challenges and Potential Solutions in Food Systems II
Chair(s): X. Pan, Solae LLC, USA; and U. Nienaber, Kraft Foods Inc., USA
Role of Reverse Micelles on Lipid Oxidation: Impact of Phospholipids on Antioxidant Activity of α-tocopherol and Trolox in Stripped Soybean Oil. B.C. Chen, D.J. McClements, E.A. Decker, Department of Food Science, University of Massachusetts, Amherst, MA, USA
Phospholipids self-assemble in bulk oils to form reverse micelles that can alter the microenvironment where chemical degradation reactions occur. In this study, we examined the influence of phospholipid reverse micelles on the activity of non-polar (α-tocopherol) and polar(Trolox) antioxidants in stripped soybean oil (SSO). Reverse micelles were formed by adding 1000 μM 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) to SSO. The addition of DOPC reverse micelles had an prooxidant effect, shortening the lag phase of SSO at 55°C. Incorporation of low antioxidant concentrations (10 μM α-tocopherol or Trolox) improved the oxidative stability of SSO containing DOPC. However, addition of high antioxidant levels (100 μM α-tocopherol or Trolox) slightly decreased the oxidative stability of SSO containing DOPC. Hydrophilic Trolox had a better antioxidative activity than hydrophobic α-tocopherol. Small angle X-ray scattering (SAXS) did not show any structure transitions when antioxidants were incorporated into the reverse micelles. Fluorescence steady state and lifetime decay measurements indicated that changes in the microenvironment of the fluorescent probe depended on antioxidant type and concentration.
Factors Affecting Generation and Fate of Hydrogen Peroxide in Polyphenol-rich Food Emulsions. L. Zhou, R. Elias, The Pennsylvania State University, University Park, PA, USA
Polyphenols are often referred to as antioxidants. However, recent studies have shown that polyphenol oxidation yields reactive oxygen species in foods, which may account for the observed prooxidant effects of these compounds under some conditions. In the present study, factors affecting the rate of hydrogen peroxide generation resulting from (-)-epigallocatechin gallate (EGCG) oxidation in oil-in-water emulsions were investigated. Peroxide production in surfactant-stabilized emulsions was dependent on EGCG concentration, and the addition of Fe or Cu increased observed peroxide concentrations, thus confirming that the overall reaction is metal-catalyzed. In protein-stabilized emulsions, peroxide concentrations were significantly lower across all treatments, and increased levels of protein carbonyls were also observed, suggesting that peroxide was scavenged by the protein. To further explore this possibility, hydrogen peroxide was added to solutions containing varying concentrations of casein or whey protein. Both proteins showed concentration dependent peroxide scavenging with casein displaying higher scavenging abilities compared to whey protein. We hypothesize that methionine accessibility to the solvent phase in these proteins may play a role in the varied peroxide scavenging capacities, as methionine is known to quench peroxide species.
Evaluation of Natural Rosemary and Green Tea Extracts on Frying Performance of RBD Palm Oil. S. Sumankeerthi, N. Waize, S. Sabari Rajan, W. Schroeder, Kemin Food Technologies, Des Moines, IA, USA
Physico-chemical changes in refined, bleached and deodorized (RBD) palm oil during deep-fat frying and on sensory acceptability of French fries was studied for various additives. Deep-fat frying of French fries was carried at 185±20C for 5 consecutive days (10 frying cycles per day). The treatments included RBD palm oil without antioxidant (control negative), with 200 ppm TBHQ (positive control), 1000 ppm of proprietary rosemary and 500 ppm of proprietary green tea. The effectiveness of the treatments were measured as the efficiency to prevent oxidation of oil by lowering the rate of increase in PV, FFA content, AV, absorbance at 233 nm and improving the induction time over the 50 frying cycle period. The results of the parameters analyzed revealed that all the treated oil samples were significantly different from the control negative (p<0.05). Within the treated oil samples, all the groups were significantly different from one another (p<0.05). The order of effectiveness of natural extracts was found to be green tea > TBHQ > rosemary. The sensory evaluation of French fries showed that there was no significant (p>0.05) difference between treatments except for the negative control. The current study demonstrates that the green tea extract performed significantly (p<0.05) better than all other treatments, including TBHQ.
Increased Oleic Vegetable Oils for Improved Frying Performance: Comparative Stability of High Oleic Canola, High Oleic Sunflower, Mid-Oleic Sunflower, and High Oleic Soybean Oil. Michelle Peitz, Archer Daniels Midland, Decatur, IL USA
This laboratory study looks at the frying stability of High Oleic Canola, High Oleic Sunflower, and Mid-Oleic Sunflower, and High Oleic Soybean Oil over a 10 day period. Forty-six kg of potatoes were fried per 6.8 kg fryer over the period of time and the potatoes were analyzed for sensory properties. The oils were analyzed for degradation products and changes in quality. Results showed that the oils with higher levels of oleic and lower levels of polyunsaturated fatty acids had excellent frying performance. Sensory results showed very little difference between the oils and eating quality was maintained through 10 days of oil use. Results from this study further emphasize the benefits of using high stability oils in frying applications.
Oxidative Stability and Physical Properties of the Interesterified Hard Fat from Soybean Oil, Palm Stearin and Conjugated Linoleic Acid through Lipase-Catalyzed Reaction. Prakash Adhikari1, Peng Hu1, Xuebing Xu1,2, 1Wilmar Biotechnology Research and Development Center, Gaodong Road, Pudong New District, Shanghai,China, 2University of Aarhus, Denmark
Interesterified hard fat (IEHF) was produced from soybean oil (SBO) and palm stearin (PS) using two different ratios of substrates. Lipozyme TL IM (10%) was used as a biocatalyst. Conjugated linoleic acid (CLA; 10 wt%) was used as a functional fatty acid. Comparative study was carried out between IEHF and physical blends for the quantification of physical properties, (i.e., solid fat content, melting and crystallization behavior). From NMR results, physical blends showed higher solid fat content than IEHF at each measured temperatures. The Rancimat test was performed for the oxidative stability where the IEHF showed significantly lower induction time than physical blends. When the antioxidants (BHT, BHA, rosemary, TBHQ, PG, AP, 100 and 200 ppm) were added to the IEHF, the induction time was significantly increased. In this study, IEHF that may have a potential functionality for the margarines and shortenings were produced and their oxidative stability was observed.
Effect of the Oxidative Stability and Nutritional Property of Rice Bran Oil Blended with Other Oils. Prachi Srivastava , R.P. Singh, H.B.T.I., KANPUR, Kanpur, India
The objective of this study was to work out different blends of oils amongst rice bran oil (RBO), soybean oil (SBO), and mustard oil (MO) to obtain a unique blend of oil having better shelf life on the basis of induction time with the help of Rancimat 743 (Swiss made) as well as better SMP ratio and omega-6/omega-3 ratio. The results of experiment show that if RBO, SBO and MO are blended in proportion of 3:1:1, it results in maximum oxidative stability up to 9.31h at 110 C without adding any antioxidants in comparison to other blends. From nutritional point of view the study of SMP ratio and omega-6/omega-3 ratio were also evaluated on the basis of fatty acid composition of blends with the help of GLC. The results show that SMP ratio and omega-6/omega-3 ratio of this blend was approximately 1:2.6:2.2 and 7:1 respectively. This study concludes that the blend of RBO, SBO and MO in proportion of 3:1:1 resulted in proper ratio of omega-6/omega-3, however, there is variation in SMP ratio from the one recommended by WHO .
ANA 3.1 / LOQ 3: Antioxidants and Oxidation Control: Analytical Methodologies and Efficacies
Chair(s): D. Luthria, USDA, ARS, USA; and F. Shahidi, Memorial University of Newfoundland, Canada
Efficacy and Measurement of Antioxidants. F. Shahidi, Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, Canada
Antioxidants in food and biological systems have received increasing attention in recent years due to better appreciation of their role in food preservation as well as in health promotion and disease risk reduction. The efficacy of antioxidants from natural origin in foods depends on the source material, activity of the relevant phytochemicals related to their structural characteristics and lipophilicity/hydrophilicity. In addition, concentration of antioxidants, presence of other food constituents and storage conditions, among others, are important factors affecting antioxidant activity. The mechanism of action of antioxidants may be quite varied and testing of their efficacy should include several assays that are complementary to one another. In addition, sampling techniques as well as release of bound antioxidants from food matrix is essential when correlating in-vitro data with in-vivo results.
Comparison of Extraction Solvents on Assay of Phenolics Form Foods. Devanand Luthria, USDA, ARS, ERRC, USA
Increased interest in bioactive food components and phytochemicals has arisen from numerous epidemiological studies that suggest that certain phytochemicals can reduce risk of chronic diseases. This presentation will illustrates with examples the significance of optimization of extraction procedures in developing analytical methodologies for accurate estimation of bioactive compounds present in foods and dietary supplements. It will discuss the importance of different sample preparation parameters such as extraction solvent composition, solid-to-solvent ratio, temperature, and particle size for the accurate assay of phenolic compounds in different food matrices. Furthermore, effect of drying and grinding procedures on the assay of phenolic compounds from plant and food samples will also be presented. A comparison of current (pressurized-liquid, ultrasonic irradiation, and microwave-assisted) and classical (stirring, Soxhlet, shaker, vortex) extraction procedures on the assay of phenolic phytochemicals will also be discussed. A systematic protocol for optimizing sample preparation procedure for extraction and assay of phytochemicals from different plant matrices will also be presented. Accurate analysis of bioactive compounds is critical for their precise and reproducible quantification in different foods, establishing appropriate dietary intake and safety guidelines, and understanding their role in human health and nutrition.
Extraction and Analysis of Soluble and Bound Fruit Polyphenols. L. Howard, B. White, University of Arkansas, Dept. Food Science, Fayetteville, AR, USA
Polyphenols in fruits and their co-products are typically extracted with aqueous-organic solvent mixtures prior to HPLC analysis or determination of antioxidant capacity. Evidence is increasing that significant quantities of polyphenols in fruits, especially hydrolysable and condensed tannins are entrapped or bound to cell wall polysaccharides and resist extraction using conventional extraction techniques, suggesting levels of fruit polyphenols reported in the literature have been vastly underestimated. The release of bound polyphenols from fruits following conventional extraction can be performed using acid or alkaline hydrolysis methods, but both methods have limitations due to the lability of polyphenols and formation of side products under harsh chemical conditions, and lack of authentic standards for quantification. These methods along with their advantages and disadvantages will be discussed as well as the potential implication of bound polyphenols on gastrointestinal health.
Challenges with Antioxidant Analysis: Strengths and Weaknesses. W. Ellefson, D. Sullivan, Covance Laboratories, Madison, WI, USA
Today’s marketplace reflects consumers demand for healthy products. Products that are high in antioxidant content are one area of major interest. There are a variety of general methods (ORAC, DPPH, Folin-C, FRAP, etc.) to measure antioxidant potential. In addition there are many methods that assess the level of individual categories (e.g., catechins, isoflavones, etc.) or individual compounds. All methods have strengths and weaknesses. This presentation will focus primarily on these strengths and weaknesses. An overview of the application of a selected number of these methods will be presented along with estimates of what compounds each test is capable of measuring. Specific examples will be highlighted, including the stability indicating nature of some of these test methods. This discussion will provide an overview of many of the analytical techniques and highlight the need for harmonized methods of analysis. Some of these methods have more specific applications with selected matrices, while others have a broader application. When there are numerous methods for the same analyte there is significant room for disagreement. We will highlight a process to come together, discuss common methods, agree on an approach, and complete a study to develop `gold’ standard methods that everyone can accept. This AOAC process has been extremely successful for 125 years. Methods that successfully navigate this process are widely accepted by government agencies around the world and stand up in courts of law.
Can Antioxidant Activity Assays be Redirected to Guide Stabilization of Foods with Natural Compounds? K.M. Schaich, Rutgers University, New Brunswick, NJ, USA
A plethora of antioxidant activity assays have been developed to test putative antiradical action of natural compounds and extracts, and results are being widely used to predict protective effects in vivo. However, such application is being increasingly questioned due to very low absorption of phenols, rapid conjugation and elimination, and mounting evidence that phenolic compounds exert their effects through a variety of signal transduction pathways. Arguments will be presented for productively redirecting antioxidant assays to identify compounds with promise for replacing BHA and BHT in foods. Which assay(s) will most accurately predict phenol effects in food systems – H atom transfers or electron transfers? What new assays must be developed to supplement established assays? Predicting effects in foods will require modification of current antioxidant assays to provide kinetic and mechanistic information as well as stoichiometric measures of antioxidant reactions, increased attention to synergisms and antagonisms between polyphenols, consideration of phase partitioning, and determination of protein binding effects on phenol reactivity and availability in foods. Strategies for determining appropriate natural antioxidants and delivery modes for various food applications will be described.
Dietary Modulation of Oxidative Stress: Physiological Meaning of the Non Enzymatic Antioxidant Capacity (NEAC). Mauro Serafini, National Institute for Food and Nutrition Research (INRAN), Rome, Italy
Diet-derived antioxidants have been proposed to reduce oxidative stress-related disease development. However, contrasting results from clinical trials have raised strong concerns about the importance of antioxidants on human health. A vulnerable point of the research on antioxidants is the lack of information on the effect of the whole array of antioxidants in disease prevention, as so far mainly single galenic molecules have been investigated. Despite many food items rich in antioxidants have been accredited of an antioxidant action in vivo, the extent to which plant foods are able to tune oxidative stress in human is unclear and it represents a matter of debate. The first systematic review of dietary intervention studies with plant foods on markers of antioxidant function will be presented and the association between dietary and endogenous antioxidant defenses in vivo will be discussed in order to obtain a realistic portrait of the complex interactions at the basis of the postulated protective effect of antioxidants molecules. There is a strong need of increasing the existing knowledge on the real efficacy of antioxidants in vivo in order to clarify if redox molecules represent a scientific-based strategy for disease prevention or just ancillary ingredients of fruit and vegetables.
Methods for Assaying Antioxidants in Lipids and Emulsion Systems. D. Huang, Department of Chemistry, National University of Singapore, Singapore
High throughput assays have been developed for rapid measurements of antioxidant capacity in bulk oil and microemulsion (oil-in-water) with methyl linoleate as the substrate in both cases. A oxygen sensitive fluorescent probe coated 96-well microplate, Oxygen Biosensor SystemTM, were applied to conveniently monitor the oxygen concentration change kinetics during the autoxidation. From the area under the kinetic curves, the antioxidant capacity of food lipids and polyphenolic compounds were calculated using Trolox as the standard. In the microemulsion system, the synergistic effect of hydrophilic antioxidants and α-tocopherol was measured for representative flavonoids. Chlorogenic acid has the best synergistic effect of 44.8%. The assays, coined as ORACoil and ORACE (for microemulsion) provides a model system in evaluating antioxidant capacity of phenolic compounds in a heterogeneous system relevant to food and cosmetic applications.
LOQ 4 / H&N 4.1: Omega-3 Challenges: Stability, Processing, and Human Nutrition
Chair(s): S. Raatz, USDA, ARS, NPA, USA; S.-J. Yoo, Martek Biosciences Corp., USA; and S.-C. Liang, DuPont, USA
Everything You Wanted to Know About DHA. N. Salem, A. Ryan, Martek Biosciences Corp., Columbia, MD, USA
One frequently asked question concerning omega-3 fatty acids is "Which one do I need?" Alpha-linolenic acid (ALA) is predominant in the Western diet and the extent to which it is metabolized to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) will determine its efficacy in meeting requirements for the longer chain, more unsaturated n-3 fatty acids. Many compositional and stable isotope studies have indicated that ALA metabolism in higher mammals (cats, dogs and primates) occurs but is very limited and does not lead to increases in blood stream DHA, although EPA and DPAn-3 are generally increased. Thus preformed DHA is required in the diet to support higher organ DHA content and nervous system DHA, in particular. Increased organ and nervous system DHA does, in turn, yield many benefits for physiological function and health. Conversely, deficiency of n-3 fatty acids leads to many deficits in function with the nervous system the most studied organ in this respect. Some recent clinical study results in which DHA supplements were given will be summarized. Recent findings have indicated a benefit for cognitive function maintenance during normal aging leading to interest in possible uses of DHA for treatment of dementias or amelioration of their symptomology.
Linoleic Acid-specific and Mixed Polyunsaturate Dietary Interventions have Different Effects on CHD Risk: A Meta-analysis of Randomised Controlled Trials. C. Ramsden1, J. Hibbeln1, S. Majchrzak1, J. Davis2, 1National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA, 2University of Illinois at Chicago, Chicago, IL, USA
Randomized controlled trials (RCTs) of mixed PUFA diets, and meta-analyses of their CHD outcomes, are considered convincing evidence in specifically advising consumption of "at least 5-10% of energy as n-6 PUFAs”. Here we: 1) extracted detailed dietary and outcome data enabling a critical examination of all relevant RCTs; 2) determined if diets increased n-6 PUFAs specifically, or increased both n-3 and n-6 PUFAs (i.e. mixed n-3/n-6 PUFA diets); and 3) compared mixed n-3/n-6 to n-6 specific PUFA diets on CHD outcomes. n-3 PUFAs were increased substantially in 4 of 8 datasets and n-6 linoleic acid was raised with specificity in 4 datasets. For non-fatal myocardial infarction(MI)+CHD death, pooled risk reduction for mixed n-3/n-6 PUFA diets was 22% (RR=0.78 95%CI 0.65-0.93), compared to an increased risk of 13% for n-6 specific PUFA diets (RR=1.13 95%CI 0.84-1.53). Risk of non-fatal MI+CHD death was significantly higher in n-6 specific PUFA compared to mixed n-3/n-6 diets (Q=5.4, p=0.02). RCTs that substituted n-6 PUFAs for TFA and SFA without increasing n-3 PUFAs produced an increase in risk of death (RR=1.16 95%CI 0.95-1.42). Advice to specifically increase n-6 PUFA intake, based on mixed n-3/n-6 RCT data, is unlikely to provide intended benefits.
**Canceled** Current Omega-3 Oil Enrichment Technologies. P. Lembke, Bioseutica Usa, Inc., USA
Use of n-3 Oil Seed Meals in Livestock Rations as a Source of n-3 Enriched Foods. Eric Murphy, University of North Dakota, Grand Forks, North Dakota USA
Oil seed meals from flax and camelina are sources dietary of alpha-linolenic acid (ALA) for use in livestock rations. Camelina meal is an excellent source of protein, energy, and n-3 fatty acids for use in poultry rations. In laying hens, camelina meal provides ALA for conversion to longer chain n-3 fatty acids providing an n-3 enriched egg, while also providing a meal rich in protein and balanced with n-6 fatty acids. Similarly, it is a dietary n-3 fatty acid source for conversion in broilers to longer chain n-3 fatty acids found in muscle. Because camelina is an emerging oil seed crop used as a source of oil for conversion to biofuels, the meal is an important additional source of value and adds a valuable meal into the livestock market. Ground flax is another source of ALA and we have used flax extensively as a dietary source of ALA in cattle. In cattle, we demonstrate a marked increase in longer chain n-3 fatty acids as well as an increased expression of PPARγ and adipocyte fatty acid binding protein (A-FABP). In the end, these studies demonstrate that meals from camelina and flax can add value to livestock products due to the enrichment in n-3 fatty acids thereby providing a more healthy product for consumers.
Linolenic Acid (ALA): Stability, Processing, and Human Nutrition. K.C. Fitzpatrick, Flax Council of Canada, Canada
Linolenic acid (ALA) is a major dietary (n-3) fatty acid. ALA is converted to longer-chain (n-3) PUFA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The efficiency with which this conversion occurs and the factors that may modify it could have important public health implications. Efficacy of the conversion is affected by both amount of ALA fed and the linoleic (n-6) to ALA ratio. ALA plays an important role in growth and development, reproduction and vision; in maintaining healthy skin and cell structure; in the metabolism of cholesterol and in gene regulation. ALA has been linked to the prevention and/or amelioration of several chronic conditions including cardiovascular disease, rheumatoid arthritis and autoimmune disorders. Because of limitations in increasing the public's consumption of fish, the use of the plant-based (n-3) PUFA, ALA, may be an important alternative for providing optimal EPA and DHA concentrations in the plasma and cell membranes. ALA is the most commonly consumed n-3 fatty acid in the typical Western diet with flaxseed being an important source. Flaxseed and oil can be incorporated into common dietary items such as breads, rolls, cereals, muffins, margarines, and salad dressings. This presentation will describe the challenges related to communicating the health benefits of ALA and use in various food applications.
Correlation of PUFA Profiles and Cognitive Impairment in Participants in the Cache County Study on Memory Health and Aging. R.E. Ward, H. Wengreen, L. Ward, D. Pearce, Utah State University, Logan, UT, USA
To investigate the relationship between red blood cell PUFA and mild cognitive impairment the fatty acid profile of RBCs was analyzed from samples collected in the third wave of the study (2002-2004). RBCs were subjected to direct transesterification with acetylchloide in methanol and analyzed via gas chromatography with flame ionization detection. In total, we analyzed the RBC profiles of 1,795 individuals from Wave 3 of the Cache County Study and compared the results to several data parameters associated with the subjects. There was no effect of age or sex, but was for BMI. The most interesting significant effects were the association of the Omega-3 index with fatty fish consumption and with Wave 3 3MS scores, a measure of cognition. According to the results, the RBC Omega-3 index is positively and significantly associated with improved cognition. While the effect was not significant for Dementia, the trend was for protection.The results for the n6 HUFA were very similar to the Omega-3 index. These measures are similar, yet the former potentially accounts for potential negative effects of high dietary n6 fatty acids. According to the data, the Omega-3 index (RBC EPA +DHA) can account for most of the protection against cognitive decline.
Processing and Stability of Omega-3 Oil from Microbial Sources. R.D. Orlandi, K.W. Hutchenson, M. Avogousti, J.M. Odom, S.-C. Liang, DuPont Applied BioSciences, Wilmington, DE, USA
Omega-3 fatty acids have been widely studied for their health benefits. There is abundant scientific evidence supporting the beneficial effects of these fatty acids, especially EPA and DHA. While fish currently remains the main source for EPA and DHA Omega-3 oil, there is growing interest and demand for microbial sources of Omega-3 oil, which is shown to have similar or better oxidative stability and is free of environmental contaminants. While there are many commonalities in oil processing between the microbial and marine sources, there are some unique aspects about extracting, refining, and stabilizing microbial oil in order to achieve the desired product quality. In this presentation, we will review various extraction methods and technologies pertaining to microbial oil. We will also cover some of the developments in oil extraction using supercritical CO2 technology, and the stability of the extracted crude oil.
Modeling the Kinetics of Fish Oil Oxidation. J.C. Sullivan1, S.M. Budge1, M St-Onge2, 1Dalhousie University, Halifax, NS, Canada, 2Ascenta Health, Dartmouth, NS, Canada
The quality of commercial fish oil products can be difficult to maintain because of the rapid oxidation attributable to the high number of polyunsaturated fatty acids (PUFA), specifically eicosapentaenoic acid (EPA ) docosahexaenoic acid (DHA). While it is known that oxidation in fish oil is generally the result of a direct interaction with oxygen and fatty acids, there are very few studies that investigate the oxidation kinetics of fish oil supplements. This study uses hydroperoxides, a primary oxidation product, to model the oxidation kinetics of two commercially available fish oil supplements with different EPA and DHA contents. Pseudo first order kinetics were assumed, and rate constants were determined for temperatures between 4 and 60 °C. This data was fit to the Arrhenius model, and activation energies (Ea) were determined for each sample. Both Ea agreed with values found in literature, with the lower PUFA sample having a lower Ea. The oil with a lower PUFA content fit the first-order kinetics model at temperatures ≥ 20 °C and ≤ 40 °C, while the higher PUFA oil demonstrated first-order kinetics at temperatures ≥ 4 °C and ≤ 40 °C. When the temperature was raised to 60 °C, the model no longer applied. This indicates that accelerated testing of fish oil should be conducted at temperatures ≤ 40 °C.
Emulsification Technique Affects Oxidative Stability of Fish Oil-in-Water Emulsions. A.F. Horn1, L.H.S. Jensen2,3, N.S. Nielsen1, A. Horsewell2,3, C. Jacobsen1, 1National Food Institute, Technical University of Denmark, Kgs Lyngby, Denmark, 2Center for Electron Nanoscopy, Technical University of Denmark, Kgs Lyngby, Denmark, 3Department of Mechanical Engineering, Technical University of Denmark, Kgs Lyngby, Denmark
In oil-in-water emulsions, lipid oxidation is expected to be initiated at the oil-water interface. The properties of the emulsifier used, and the structure at the interface is therefore expected to be of great importance for lipid oxidation in emulsions. Previous studies have shown that e.g. homogenization pressure can affect how proteins locate themselves at the interface of an emulsion. The hypothesis is therefore that emulsions produced with different emulsification equipments differ in their oxidative stability due to differences in the behaviour of the proteins at the interface. The aim of this study was therefore to compare lipid oxidation in 10% fish oil-in-water emulsions prepared by two different kinds of high pressure homogenizers i.e. a microfluidizer and a two valve high pressure homogenizer. Emulsions were made with equal droplet sizes, and with either 1% sodium caseinate or 1% whey protein isolate. Emulsions were characterised and investigated by microscopy. Lipid oxidation was assessed by PV and the formation of secondary volatile oxidation products. Results showed that the different emulsification techniques had an influence on lipid oxidation and that the effect of the emulsification technique depended on the type of protein used as an emulsifier.
Quality and Technical Challenges Facing the Omega-3 Industry as a Result of Sustained Rapid Market Growth. A. Ismail, Global Organization for EPA and DHA Omega-3s, Salt Lake City, UT, USA
The market for omega-3 fatty acids has experienced rapid growth for more than two decades. While the growth has been driven by science, specific quality initiatives by the industry have prevented quality problems from derailing the growth trajectory of omega-3s. The industry growth has brought a number of new entrants, research into new sources of EPA and DHA, and increasing regulatory attention to the space. Various governments have instituted new rules for hygiene and contaminants related to omega-3s, while literature shows that there are still many products that can bring negative attention to the space by producing low quality products. Additionally, new technical methods are being developed that will allow for greater quality assurance and traceability, but they have not yet become generally accepted standards. It is imperative that the industry continue to innovate on quality and analytical issues in order to provide a solid foundation for growth.
LOQ 5: General Oxidation
Chair(s): M. Peitz, Archer Daniels Midland Co., USA; and S. Zhou, Kellogg, USA
Thermal Desorption Studies of Corn Oil Degradation at High Temperatures. X. Qin, K.M. Schaich, Rutgers University, New Brunswick, NJ, USA
Thermal degradation processes in heated corn oil were studied using thermal desorption techniques to detect released volatiles and derive degradation reaction sequences. Oils dispersed on Celite adsorbent to increase surface area were heated in thermal desorption tubes under air and nitrogen at temperatures ranging from 100 to 235 C for two hours. Volatiles were vented into fresh Tenax-carboxen traps every 5-15 minutes to limit the number of products present and provide a map of product changes over time. Products were desorbed onto an Equity 5 GC column using a dry ice trap to retain low mol wt products, separated with temperature programming, then identified by mass spectrometry and comparison to standards. At 100 and 120C, oxidation was slow; products were few and specific. Major product shifts occurred between 120C and 150C and again at 235C, with exponential increase in both rates of degradation and numbers of different products generated. Above 150C, complex product mixtures containing C-3 to C-12 alkanes, alkenes, aldehydes, and fatty acids formed within minutes under nitrogen. Corresponding oxygenated products formed under air; only low levels of expected autoxidation products were detected. Results support radicals from thermal scissions as major mediators of thermal degradation in oils.
Incorporation of Soymega™ (stearidonic acid enriched soybean oil) into a Variety of Processed Meat Applications. S. Lee, M. Orcutt, D. Welsby, Solae, LLC, St. Louis, MO, USA
Processed meat product is one of the most popular food categories for US consumers; however, since consumers' interests in health keep increasing, and omega 3 started having an attention, it would be beneficial to use processed meat products as an omega 3 carriers. Soymega™, stearidonic acid (C18:4, n-3; SDA) enriched soybean oil, is a heart healthy and plant-based sustainable source of omega-3 fatty acid, and has been used successfully in a variety of food applications as an alternative source of omega 3s. This study was carried out to investigate the use of Soymega™ in 3 different types of processed meat application (dry sausage, whole muscle, and ground meat). Pepperoni, smoked ham and fresh pork sausages were produced using standard process procedure. Soymega™ was incorporated into each product, and commercial soybean oil was used as Control. Pepperoni and fresh pork sausages showed no significant differences between Control and Soymega™ in all attributes. Smoked hams with Soymega™ showed higher intensity than Control in overall flavor and fishy/pondy complex: however, fishy/pondy complex was below the recognition threshold. Soymega™ appeared to be stable in all processed meat products produced.
The Partitioning of Sinapic Acid, Ferulic Acid, Caffeic Acid and 4-vinyl Syringol within Oil-in-Water Emulsion Systems. A. Richards1, M. Jaffrelo1,2, P. Fagan1, C. Ceccato1, A. Hillier1, 1CSIRO, Werribee, VIC, Australia, 2IPB ENSCBP, Bordeaux, France
Lipid oxidation within emulsion systems is partially governed by interfacial dynamics. Antioxidants partition between the two phases of an oil-in-water (o/w) emulsion, and their location at equilibrium is dependant upon the molecules lipophilic nature thereby affect its ability to protect against oxidative deterioration. As such, it is believed that phenolic components that are less lipophilic will more likely locate at the emulsion interface compared with a more lipophilic compound, and therefore more effective in protecting the emulsion system to oxidative deterioration. Sinapic acid, ferulic acid, caffeic acid and 4-vinyl syringol have been identified in canola seed meal and/or oil. In order to characterise the lipophilicity of these antioxidants, distribution coefficients (Log D) were determined using UV spectrometry at three different pH. Sinapic and caffeic acid were shown to be the most lipophobic compounds under all conditions of this study. In contrast, log D for 4-vinyl syringol was independent of pH and was the most lipophilic. Therefore, sinapic and caffeic acid should be the most efficient in providing protection towards oxidative deterioraion within o/w emulsion systems compared with 4-vinyl syringol and ferulic acid.
A Spectroscopic Approach for Controlling Chemical Changes in Frying Oils. D.L. Garcia Gonzalez, N. Tena, R. Aparicio, Instituto de la Grasa (CSIC), Sevilla, Spain
Many methods have been developed to guide frying oil turnover, including the determination of free fatty acids, total polar compounds, alkaline materials (soaps), Lovibond color, metals, anisidine value, peroxide value, and mono- and diglycerides. Some rapid methods have been proposed as alternatives to the lengthy official methods, although most of them are based on indirect measurements of partial changes that take place during frying and they may not be related to quality decay or safety issues. Under this basis, spectroscopic techniques have been explored to measure the concentration and evolution of chemical species that are directly involved in quality and stability of frying oils. The possibilities of the FTIR-ATR technique have been studied to predict the percentage of total polar compounds in virgin olive oil heated at frying temperatures. For this purpose, a mathematical procedure selected the best wavelength regions for predicting the quality parameters and a predictor model was developed and validated. Following the same procedure, fluorescence spectra were acquired and processed at different conditions to study the main spectral changes. The results obtained from all the spectra were supported by chromatographic analysis (GC and HPLC) of the main chemical compounds that evolve during frying and are responsible for the spectroscopic bands.
Protein-stabilized Interfaces Do Not Protect Emulsified Lipids Against Oxidation in Comparison with Surfactant-Stabilized Interfaces. C. Berton, M.H. Ropers, C. Genot, UR1268 Biopolymères Interactions Assemblages, INRA, F-44316 Nantes, France
Food matrices are complex multiphase systems usually modelled as oil-in-water emulsions. Many studies show that the emulsifier (i.e. protein vs surfactants, charge) determines widely the oxidation rate of polyunsaturated lipids in emulsions. In these systems, the interface between oil and water is assumed to govern lipid oxidation. However, the experiments have been generally carried out with a large excess of unadsorbed emulsifiers in the aqueous phase, which may intervene in the oxidation reaction. The role of the interface on lipid oxidation has therefore not been clearly elucidated yet.To clarify the role of the interface on lipid oxidation in oil-in-water emulsions, we designed rapeseed-oil based emulsions stabilized with emulsifiers of several structures in taking care to minimize the amount of unadsorbed emulsifiers. Chosen emulsifiers included milk proteins, non-ionic and anionic surfactants, used alone or mixed together.Surprisingly, emulsions stabilized with surfactants oxidized slower than emulsions stabilized with proteins, whatever the incubation conditions. Our results are presented in a way that highlights the relationship between the interfacial layer and lipid oxidation in emulsions.
Evaluating a Combined Adsorption Process for Purifying Salmon (Oncorhynchus nerka) Oil. Huaixia Yin, Subramaniam Sathivel, Louisiana State University, Baton Rouge, LA, USA
Unpurified salmon oil (UPS) is an abundant source of polyunsaturated fatty acids and requires well-designed purification steps to improve its quality. The objective of this study was to determine the effect of activated earth, activated alumina and/or chitosan as adsorbents to remove free fatty acids (FFA) and oxidative components and moisture (MO) from UPS. Five different adsorption processes were used to purify UPS: processes 1, 2, and 3 involved purification of UPS by 5% chitosan (wt/wt of oil), 5% activated earth, and 5% activated alumina, respectively, process 4 involved the combined UPS purification processes of 5% chitosan, 1.5% chitosan plus 3.5% activated earth, and 5% activated alumina, and process 5 involved the combined UPS purification processes of 5% chitosan, 4% chitosan plus 1% activated earth, and 5% activated alumina. Triplicate experiments were conducted at 25ºC and data were statistically analyzed using α=0.05. All the processed salmon oils had similar fatty acid profile (FA) and iodine value (IV). Processes 4 and 5 were effective in reducing PV, FFA, and MO in UPS than processes 1, 2, and 3. This study demonstrated that the combined adsorption processes could produce purified salmon oil by reducing the FFA, PV, and MO of UPS.
Choline and Ethanolamine Decompose Lipid Hydroperoxides into Hydroxyl Lipids. X. Pan, A. Irwin, M. Leonard, D. Welsby, Solae, LLC, USA
Analysis of lipid hydroperoxides and hydroxyl lipids in food and biological systems has historically been difficult due to the instability and diversity of these compounds as well as the complexity of the associated purification and derivatization processes. A rapid, high throughput and robust method based on mass spectrometry using multiple reaction monitoring mode of LC-ESI-MS/MS has been developed for the simultaneous quantitative analysis of fatty acid hydroperoxides and hydroxyl fatty acids without purification or derivatization. The method has been used to demonstrate that functional groups of phospholipids, choline and ethanolamine, are capable of decomposing lipid hydroperoxides into their corresponding hydroxyl lipids. In model systems where choline and ethanolamine were added, the amounts of lipid hydroperoxide isomers decreased while the amounts of hydroxyl lipids increased. In similar model systems containing normal food antioxidants such as tocopherols and butylated hydroxytoluene, and in the control without antioxidants, the amounts of lipid hydroperoxide and hydroxyl lipids did not change significantly under current experimental conditions.
**Cancelled** Novel Caffeic Acid Amide Antioxidants: Synthesis, Radical Scavenging Activity and Performance under Storage and Frying Conditions. F. Aladedunye, University of Lethbridge, Canada
|Lipid Oxidation and Quality Posters|
Chair(s): J. Gerde, Iowa State University, USA; and U. Thiyam-Hollaender, University of Manitoba, Canada
**Cancelled** Factors Affecting Generation and Fate of Hydrogen Peroxide in Polyphenol-rich Food Emulsions.
L. Zhou, The Pennsylvania State University, USA
**Cancelled** Valorization of Low Quality Edible Oil by Carotenoids Formed by Bacillus indicus HU36.
B. Ozcelik, Instanbul Technical University, Turkey
Evaluation of Changes in Physicochemical Characteristics of Edible Vegetable Oils as a Function of Fatty Acid Composition and Frying Conditions.
Mahsa Naghshineh, Hamed Mirhosseini, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
Deep fat frying is one of the oldest cooking methods widely used both at home and industrial scale in order to develop the organoleptic properties of foods. A number of physicochemical changes occur both in the frying medium and the product fried. In the presence of oxygen, food moisture and high temperature, the oil undergoes three deleterious reactions during frying process: hydrolysis caused by water, oxidation, and thermal alteration caused by oxygen and heat. However, as these reactions proceed, the functional, sensory and nutritional quality of frying fats will be changed, thereby approaching a point where high quality foods can no longer be prepared. Although, quality evaluation of frying fats may be determined in many ways, the frying industry is still searching for the ultimate criteria to evaluate frying stability of oils, quality and stability of fried-food flavor. Recently, numerous investigations were carried out with the aim of lowering oil uptake during deep fat frying. This review summarizes the physicochemical properties of edible vegetable oils as function of fatty acid composition and frying conditions.
The Changes of trans-fatty Acids in Food under Different Cooking Conditions.
Tie-Ying Zhang, Yuan-Rong Jiang, Chao Hu, Hong Yang, Wilmar (Shanghai) Biotechnology Research & Development Center Co. Ltd, China
Potential to significantly increase cardiovascular risk by trans-fatty acids (TFAs) has been confirmed by plenty of previous studies. Catering industry constitutes one important possibility of intake of TFAs. In Chinese catering industry, stir-frying is as popular as deep-frying. Therefore, investigation of TFAs changing in both stir-frying and deep-frying will give some important clues about the intake of TFAs in daily life. The aim of this research was to explore the changes of TFAs content in foods after stir-fried or deep-fried. The results indicated that the content of TFAs in deep fried chicken wings and French fries have been increased significantly (P < 0.05) to 0.178 g/100g and 0.269 g/100g, compared with 0.032 g/100g and 0.019 g/100g in the uncooked fresh foods respectively. In addition, the content of TFAs increased from 0 g/100g and 0.017 g/100g to 0.037 g/100g and 0.023 g/100g (P > 0.05) respectively after stir-frying potato chips and shredded meat. The above results indicated that the changes of TFAs content were not significant during stir-frying. Though the changes of TFAs content were increased significantly (P < 0.05) during deep-frying, the TFAs content of deep-fried foods were very lower level that were all less than 0.3 g/100g.
Influence of the Oxidation Catalyst on the Oxidative Stability of Oil-in-Water Emulsions Stabilized with Protein and Surfactant Emulsifiers.
C. Berton, M.H. Ropers, D. Guibert, Q. Pottiez, C. Genot, UR1268 Biopolymères Interactions Assemblages, INRA, F-44316 Nantes, France
Oxidation of polyunsaturated fatty acids (PUFA) is a major cause of deterioration of food quality. Oil-in-water (O/W) emulsions have been extensively used as model of food matrices to study the effect of compositional factors, such as the nature of the emulsifier on lipid oxidation. These studies were generally carried out in particular incubation conditions involving one particular initiation mode and a temperature varying from typical food storage temperature to higher ones. To extend the results we obtained with iron-EDTA catalyst concerning the impact of adsorbed emulsifier on oxidation kinetics, this work compares the influence of the oxidation catalyst on the oxidative stability of O/W emulsions stabilized with several protein or surfactant emulsifiers. Lipid oxidation was promoted by iron-ascorbate, azo initiator, metmyoglobin or by a higher incubation temperature. The order of oxidative stability for the different emulsions was overall the same whatever the incubation condition, even if some kinetic specificities for specific catalyst/emulsifier pairs could be found.
Chemical Methods, Physical and "Quick" Tests to Verify the Quality of Oils and Fats used for Frying in Poland Restaurants.
A. Mengual Domenech, K. Krygier, Warsaw University of Life Sciences, Warsaw, Poland
Oils and fats during frying undergo irreversible quality changes. Chemical alteration: hydrolysis, oxidation and polymerization expose consumer to risk of consumption fried food prepared on poor quality oil or fat. There are many methods, chemical and physical also quick test, permitting verify the quality of oils and fats used for frying. The aim of the study was to examine the quality of oils and fats used for frying in different restaurants in Poland. Samples in number of 171 were recollected from restaurants in Warsaw city and coastal regions towns. In controlled samples the content of polar compounds, acid value, smoke point and color were determined. Also some quick tests for preliminary check were used. Only 3,5% of analyzed samples exceed the most universal in European Union countries limit of 25% of polar compounds. Acid value, surpassed limit of 2,5 mg KOH/g in 10,5% of samples. The smoke point in 8,2% of samples was lower or equal than 170°C. Conducted analysis, in general, revealed good quality of oils and fats used for frying in Polish restaurants. Scientific study founded from financial resources of polish budget for science in 2010-2012 year, as research project.
Cultivar Effect on the Phenolics of Olive Leaves and their Antioxidant Activity.
Michail Syrpas1,3, Vera Van Hoed1, Cristof Van Poucke2, Sarah De Saeger2, Apostolos Kiritsakis3, Roland Verhé1, 1Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, Belgium , 2Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, Ghent, Belgium, 3Technological Educational Institution (TEI) of Thessaloniki, Thessaloniki, Greece
The purpose of this research was to analyze and asses the phenolic content of leaves of 21 different olive cultivars. Phenolic acids ,phenolic alcohols, flavonoids and their glycosylated forms and secoiridoids were identified in our samples. Oleuropein was not always the main constituent. Generally, the leaves of the various studied cultivars did not show significant differences in their phenolic profile. Total phenolic content (TPC) measured in all samples by Folin-Ciocalteu method ranged from 16,2 to 36,2 mg caffeic acid equivalent (CAE) /g dry leaves. The values obtained however when HPLC-MS method was applied were lower and varied from 4,37 to 19,57 mg of oleuropein/g dry leaves measuring for the three main phenolic compounds( oleuropein, luteolin 4/-O-glycoside, luteolin 7-O-glycoside). Antioxidant activity was evaluated for 13 cultivars. DPPH radical scavenging activity expressed as Trolox equivalent ranged from 48,21 to 140,90 μm Trolox Equivalent Antioxidant Capacity (TEAC) /g dry leaves. Two edible oils (arachidic and grape seed oil) enhanced with four different concentrations (100;200;500;700 ppm) of olive leave phenolic extract in an OSI apparatus (at 97,8 ⁰C) exhibited high resistance to oxidation. The highest resistance to oxidation was found to be in oils containing 500 ppm of phenolic extract.
Alternate Pathways of Lipid Oxidation: Looking Beyond Hydrogen Abstraction.
X. Qin, K.M. Schaich, B. Bogusz, Rutgers University, New Brunswick, NJ, USA
Replacement of saturated and trans fats with polyunsaturated oils is challenging traditional stabilization strategies. Inconsistencies of kinetic and oxidation products with classical free radical chain reactions of lipid oxidation raise questions about how lipid oxidation actually occurs. Based on data in the free radical literature, a new reaction scheme that integrates alternate lipid oxidation pathways with traditional hydrogen abstraction is proposed to more completely account for products and kinetics of lipid oxidation. Alternate pathways including addition, cyclization and scission compete with hydrogen abstraction during autoxidation; the balance between them changes with reaction conditions, altering product levels and distributions. To test these pathways and determine shifts of products under different conditions, methyl linoleate was incubated under varying conditions (temp-erature, oxygen level, lipid concentration, solvents); oxidation products from all pathways (conjugated dienes, hydroperoxides, carbonyls, epoxides and dimers) were measured over time to determine oxidation kinetics and product distributions. Results validate and refine the integrated reaction scheme, and suggest protocols for accurately assessing the true state of rancidity and more effectively stabilizing foods.
Features of Oils and Lipids Oxidation.
D.A. Krugovov1,2, O.V. Bugaichuk1, E.A. Mengele2, A.V. Alesenko1, O.T. Kasaikina2, 1Emanuel Institute of Biochemical Physics RAS, Moscow, Russia, 2Semenov Institute of Chemical Physics RAS, Moscow, Russia
Lipid oxidation is very important scientific field in nowadays for chemical-,food- and health industry. Knowledge about the rules of lipids oxidation helps to create methods to stop or to lead oxidation process to get useful products. During this study the model of lipid oxidation was created. Limonene (4-isopropenyl-1-methylcyclohexene) is natural olefin of the terpene series was used as a model substance. Limonene is wide used in composing of perfume compounds, for soap scents, and as an ecologically safe solvent. That is why the process of its oxidation is so useful as the model process.As it was determined oxidation of R(+) limonene (LH) with molecular O2 in organic solvents proceeds via the chain free radical mechanism. Mechanism of this process was studied and all constants of elementary reaction were obtained. Kinetic parameters of limonene oxidation are similar with kinetic oxidation parameters for different kind of lipids. Therefore the process of limonene oxidation is very useful as model reaction of lipid oxidation. With the help of this model influence of deferent additives on oxidation process was studied.It is well known that Alzheimer disease have influence on lipid composition of human blood. That is why oxidation status of the lipid fraction of human blood in the case of diseased people is differing than healthy. It was determined with the help of limonene oxidation model.
A DSC Study of the Thermoxidation of Chia Seed Oil: Effect of Different Antioxidants.
V.Y. Ixtaina1,2, S.M. Nolasco2, M.C. Tomás1, 1Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA) – Facultad de Ciencias Exactas (UNLP-CONICET), La Plata, Pcia. de Buenos Aires, Argentina, 2Facultad de Ingeniería (TECSE) (UNCPBA), Olavarría, Pcia. de Buenos Aires, Argentina
Chia seed oil presents a high amount of PUFAs (≈ 80%) being very susceptible to the lipid oxidation. Thermoxidation of chia seed oil was investigated under non-isothermal conditions (10-350°C) in an oxygen atmosphere. Also, the effect of the addition of different antioxidants (2500 ppm rosemary extract, 2500 ppm green tea extract, 1500 ppm tocopherols and 2500 ppm ascorbyl palmitate) to the chia seed oil was evaluated. Temperatures of the extrapolated onset and the first and second peak of the exothermic process recorded at different heating rates ranged between 139.5-168.2ºC (Tonset), 173.4-212.6ºC (Tpeak 1) and 199.8-265.1ºC (Tpeak 2). These temperatures were used to calculate the activation energies and the Arrhenius kinetic parameters of thermal-oxidative decomposition of the oil, using the Ozawa-Flynn-Wall (OFW) method. The DSC thermograms showed two peaks which are associated with the primary and secondary products of lipid oxidation, respectively. Activation energy (Ea) of the thermoxidation of chia seed oil (onset) was 67.9 kJ/mol and increased up to 89.9 kJ/mol in case of the addition of rosemary extract, 74.1 kJ/mol for green tea extract, 71.1 kJ/mol for ascorbyl palmitate and decreased to 62.9 kJ/mol for tocopherols.
Effect of Antioxidants on the Stability of Canola Oil during Deep Frying.
Reza Esmaeilzadeh Kenari1, Reza Farhoosh2, Elham Shokooh Saremi3, 1Sari, Agricultural and Natural Resources University, Iran, 2Ferdowsi University of Mashhad, Iran, 3Azad University of Jooybar, Iran
In this study, the effect of tertiary butyl hydroquinone (TBHQ), β-caroten, α-tocopherol and blend of TBHQ and α-tocopherol on the stability of canola oil (CAO) during the frying process of potato pieces at 180ºC was investigated. TBHQ and β-carotene and α-tocopherol were added to the CAO in the amount of 100 mili gram per liter (ppm) and 100 ppm blend of TBHQ and α-tocopherol to ratio 1:1 were added to the CAO. All antioxidants were used with 100 ppm citric acid as chelating agent. Frying stability of the oil samples during the frying process was measured based on total polar compounds (TPC) content, conjugated diene value (CDV), Oxidative stability index (OSI), and carbonyl value (CV). The positive effect of the blend of TBHQ and α-tocopherol on the stability of the CAO was more than that of other antioxidants during the deep frying process, but β-carotene had little impact on the stability of the CAO. Based on TPC, most frying time was about to blend of TBHQ and α-tocopherol that was appropriate for 44 hours frying.
**Cancelled** Characterization of Volatile Compounds of Aegean Olive Oils.
B. Ozcelik, Instanbul Technical University, Turkey
Stability of DHA and EPA of a Blended Oil with Different Cooking Methods.
Yuanrong Jiang, Yuquan Zhang, Junmei Liang, Fuhuan Niu, Wilmar Biotechnology R & D Center (Shanghai) Co., Ltd., Shanghai, China
In this study, blended oil with 1.5% deep sea fish oil was chosen to investigate oxidation stability when used in different cooking methods. Losses of DHA and EPA and the quality of the blended oil were measured.Deep frying and stir-frying were adopted in this study to compare the effect of different cooking styles on the stability of DHA and EPA in the cooking oil. In deep frying test, at least 85% DHA and EPA could be kept after ten times frying of French fries and five times frying of chicken wings. In stir-frying test, shredded potatoes were stir-fried for 3 minutes. After cooking, both the residue oil in the wok after removing the food and the oil extracted from food were analyzed. It turned out that up to 97% DHA and EPA could be kept in the residue oil in the wok and 94% DHA and EPA were left in the oil extracted from the food. A series blended oils containing different ratio of DHA and EPA were studied with the same experiments. Similar results were obtained. Acid value, peroxide value, p-anisidine value and carbonyl value were measured before and after cooking. All the results indicate that adding 1.5% fish oil into cooking oil is feasible for family cooking.
Correlation Between Sensory and Chemical Markers in the Evaluation of Brazil Nut Oxidative Shelf-life.
Camile Zajdenwerg1, Gabriel Branco1, Jean Alamed2, Eric Decker2, Inar Castro1, 1University of São Paulo, São Paulo, SP, Brazil, 2University of Massachusetts, Amherst, Massachusetts, USA
Sensory analysis is one of the most suitable processes for measuring oxidative damage and determining nuts' shelf-life, but it is an expensive and time-consuming methodology. Thus, our objective was to correlate sensory data and chemical markers obtained during the accelerated oxidation of Brazil nuts and to determine the chemical parameter values associated with the nuts' sensory shelf-life as established by the consumers. Brazil nuts were kept at 80oC for 21 days. The oxidized odor of the samples analyzed by 9 trained panelists and the chemical parameters were determined at intervals of 2 days. A high (r>0.95) and significant correlation (p<0.05) was observed between the sensory data and the peroxide value (PV), para-anisidine value (pAV), hexanal content and α- and γ-tocopherol concentrations. When compared with fresh samples, sensory identification of oxidized odor occurred on the 4th day, earlier than changes in chemical markers (12th day). Consumers rejected the nuts after only 12 days of storage, which corresponded to PV = 17.4 meq kg-1 oil, pAV = 11.5, hexanal = 64.35 μmol 100g-1 oil, and 14.3 mg kg-1 oil of α- and 88.2 mg kg-1 oil of γ-tocopherols. Our study suggests that simple spectrometric methods, such as PV and pAV, can be used to estimate the oxidative shelf-life of nuts based on sensory analysis.
Antioxidant Efficiency in Micro Heterogeneous Micellar Systems.
O.T. Kasaikina, E.A. Mengele, Z.S. Kartasheva, Institute of Chemical Physics RAS
The effects of localization and distribution of substrate, initiator, and antioxidant on the oxidation rate in micellar systems are considered. The conditions of antioxidant behavior of surfactants in hydrocarbon and oil oxidation were studied. Surfactants (S) were found to form mixed micelles together with amphiphilic hydroperoxides (LOOH), the primary products of hydrocarbon and oil oxidation by oxygen. Mixed micelles are as a matter of fact self-organized nanoreactors in which active polar substances such as LOOH, metal compounds, phenols, amines, etc are concentrated.Cationic surfactants were found to catalyze decomposition of hydroperoxides into free radicals and accelerate oxidation. Contrary to cationic surfactants, some anionic and nonionic surfactants were found to catalyze nonradical decomposition of ROOH. Because polar phenolic antioxidants concentrate in mixed micelles, the escape of free radicals derived from decomposition of ROOH can be decreased noticeably. It results in the decrease of initiation and consequently oxidation rates. The rate of chain transfer by inhibitor's radical decreases in reverse micelles as well. So, anionic surfactants similar to phospholipids and some nonionic surfactants demonstrate synergism in prevention of oxidation with polar phenols. Antioxidant effect of some nonionic surfactant is considered as well.
Impact of the Localization of Rosmarinate Esters in Cellular System on their Antioxidant Activity.
C. Bayrasy1, J. Lecomte1, M. Laguerre1, B. Chabi2, C. Wrutniak-Cabello2, G. Cabello2, P. Villeneuve1, 1CIRAD UMR IATE, Montpellier F-34398, France , 2INRA, UMR DMEM, Montpellier F-34398, France
The antioxidant efficiency of any molecule in emulsions or cell systems is directly linked to its location in such complex systems. Previous researches where phenolic compounds were lipophilized by an aliphatic chain varying in chain length showed that the relationship between antioxidant capacity and hydrophobicity does not follow a linear trend. For example, the study of fatty esters of rosmarinic acid (from C1 to C20 esters) showed a maximal antioxidant activity for the octyl rosmarinate in emulsion system. The objective of our study was then to understand the effect of lipophilization on antioxidants activity of rosmarinic esters in cellular system. Large series of rosmarinate esters were synthesised and their antioxidant activity was assessed with DCF assays in human dermal fibroblasts. We observed by confocal microscopy the location of rosmarinate esters in intracellular medium. Indeed, rosmarinic acid intrinsic fluorescence allows a direct visualization of its intracellular uptake. These results showed that antioxidant activity in cell depends on location of antioxidant. Thus, a better understanding of the influence of the hydrophobicity of these compounds on antioxidant activity could give new strategies of designing new antioxidants compounds with enhanced activities.
Characterization of Medium Chain Triacylglycerides (MCTs)-enriched Seed Oil from Cinnamomum camphora (lauraceae) and Antioxidant Capacity.
Jiang-Ning Hu, Ze-Yuan Deng, State Key Lab of Food Science an Technology, Nanchang University, Nanchang, China
Medium chain triacylglycerides (MCTs)-enriched oil was extracted by supercritical fluid extraction of carbon dioxide (SFE-CO2) from Cinnamomum camphora seeds. The SFE-CO2 process was optimized using Box–Behnken design (BBD). The maximum oil yield (42.82%) was obtained under the optimal SFE-CO2 conditions: extraction pressure, 21.16 MPa; extraction temperature, 45.67°C; and extraction time, 2.38 h. The physicochemical characteristics, fatty acid composition, TAG composition, DSC profile as well as anti-oxidant activity of C. camphora seed oil were studied. Results showed that C. camphora seed oil was predominately contributed by capric acid (53.27%) and lauric acid (39.93%). The predominant TAG species in C. camphora seed oil was LaCC/CLaC (ECN 32, 79.29%). Meanwhile, C. camphora seed oil exhibited ideal antioxidant capacity. Conclusively, such a high level of MCTs in C. camphora seed oil could be potentially applied for food industries.
Physicochemical Characteristics and Oxidative Stability of Perilla Oils Prepared from Different Roasting Conditions.
T.T. Zhao1, S.I. Hong1,2, N. Ma1, I.-H. Kim1, 1Department of Food Nutrition, College of Health Science, Korea University, Seoul, South Korea, 2Research Institute of Health Science, Korea University, Seoul, South Korea
The chemical composition and oxidative stability of perilla oil prepared from the seed roasted, at different roasting temperatures and times, were evaluated and compared with those of unroasted perilla oil. After roasting, the perilla oils extracted using an expeller at 150 ºC. Content of total trans fatty acid in perilla oils increased as the roasting temperature and time increased, but it exhibited no more than 0.8% at entire roasting condition. Four tocopherol isomers (α-, β-, γ-and δ-tocopherol) were identified and γ-tocopherol was shown to be the major tocopherol. Total tocopherol content was increased as the roasting temperature increased. There were significant differences in the phosphorus content, color intensity, and fluorescence of perilla oils prepared at different roasting conditions. The oxidative stability of perilla oils obtained at different roasting condition was investigated by peroxide value during storage days at 60ºC. The peroxide value of perilla oil decreased as storage day increased whereas the content of tocopherol in the perilla oil gradually decreased. Moreover, the increased roasting temperature and time lead to the decrease of oxidation of perilla oil.
Oxidative Stability of Conjugated Linoleic Acid – Rich Soy Oil.
C. Castrodale, R.R. Yettella, A. Proctor, B. Henbest, University of Arkansas, Fayetteville, AR, USA
A conjugated linoleic acid (CLA) rich soy oil (CLARSO) has been produced by photo-isomerization of linoleic acid with an iodine catalyst. Previous studies on CLA oxidation are confounding, but the oxidation of CLARSO has not been reported. The objective of this study was to examine the effects of CLA and iodine on the oxidation of CLARSO. A control of commercial soy oil (CSO) and 3 oils containing 0.35% iodine and either 0%, 8%, and 15% CLA were stored in dark for 10 days at 50 °C in 10 mL vials. Headspace oxygen and change in weight (CW) were measured daily. Results showed that CLA level had significant effect on oxygen depletion (p<0.05). The effect of iodine on oxidation was unclear. Therefore, the study was repeated with control CSO, and 8 treatment combinations of 0%, 0.175%, and 0.35% iodine, and 0%, 10%, and 20% commercial CLA added to soybean oil. These were stored under same conditions but at 65°C. Iodine level had significant effect on headspace oxygen and CW. CLARSO had greater oxygen depletion than CSO, but did not affect CW. Iodine may be a prooxidant.
Polyphenol Antioxidants from Potato Peels: Extraction Optimization and Feasibility Evaluation.
K. Chang, K. Schaich, Rutgers University, The State University of New Jersey, New Brunswick, NJ, US
Concerns for toxicity of synthetic antioxidants and increasing demands for zero waste initiated this investigation testing feasibility of potato peels as a source of antioxidants to retard lipid oxidation in food systems. Peels from three varieties of potatoes were extracted manually and by accelerated solvent extraction (ASE) using methanol, ethanol, 2:1 chloroform methanol (CM), and deionized water, with and without 1 % HCl. ASE extractions give higher yields in shorter times for organic solvents, but longer extractions are required for water to solubilize compounds. Phenol yields without acid ranged from 9 mg/gdw in water to 18-20 mg/gdw in methanol and ethanol. HCl had mixed effects, dramatically increasing extract yields and phenols in water (84 mg/gdw), with lesser increase in EtOH and decreased phenols in MeOH and CM extracts. Apparently acid releases water-soluble phenols bound to biopolymers but may hydrolyze more hydrophobic phenols. Acid-released water-soluble phenols were not very efficient radical scavengers (ORAC 10000 μM TE/ng phenol), but highly active lipophilic antioxidants were present in MeOH-HCl and CM-HCl extracts (ORAC =35000 and 78600 μM TE/ng phenol, respectively). LC-MS analyses are underway to identify phenols in each extract. Results support feasibility of using potato peels as a source of food grade antioxidants.
Phenolic Content of Crude and Refined Canola Oil Samples: Sinapic Acid Derivatives and Canolol.
A. Richards1, H. Dayanidhi2, U. Thiyam-Hollaender2, 1CSIRO Food and Nutritional Sciences, Werribee, VIC, Australia, 2The University of Manitoba, Department of Human Nutritional Sciences, Winnipeg, MB, Canada
The purpose of this research was to analyze and assess the phenolic content of crude and refined canola oils. Sinapic acid derivatives (SAEs) and canolol (CL) was the primary target. We identified SAEs and CL in Australian and Canadian industrial oil samples as well as laboratory extracted oil using DAD-HPLC. CL is the main constituent in all crude oils. Total phenolic content (TPC) was measured in all samples by Folin-Ciocalteu method ranged from 16.2 to 36.2 mg(SAE)/g. DPPH free radical scavenging effect will be taken into account.
Quantification of 4-hydroxy-2-hexenal and 4-hydroxy-2-nonenal in Vegetable and Marine Lipids.
C. Genot, INRA UR1268 Biopolymers Intercations Assemblies, France
Antioxidant Determination in Juices and Wines.
N.P. Khrameeva1, K.V. Shtein 1, O.T. Kasaikina 2, 1Plekhanov Russian Economy Academy, Moscow, Russia, 2Semenov Institute of Chemical Physics, Moscow, Russia
Phenolic compounds have an important impact on the organoleptic properties of juices and wines, including color and astringency. They possess antioxidant activity and are associated with possible health benefits. Pomegranate juice contains antioxidants, especially polyphenols, at higher levels than do other fruit juices. The aim of the study is to determine common antioxidant capacity in various pomegranate juices and in some red and white wines by means of potentiometric evaluation of antioxidant activity in liquids, based on the Ðš4[Fe(CN)6]/Ðš3[Fe(CN)6] mediator system (Brainina Kh.Z., et al (2007) Talanta 71,13) and to compare the results obtained with the ORAC, and colored polyphenolic substances content. Multifunctional potentiometric analyzers equipped with two-electrode electrochemical cell and platinum screen-printed electrode were used for potential metrology. A number of red and white wines and different samples of pomegranate juice and liquid obtained from fresh pomegranate grains (L) were studied. The antioxidant capacities of wines and juices were found to differ strongly/ The ratio of optical absorption at 510 nm decreased in similar row however not so sharply. ORAC measurements took much more time and showed similar relative results.
Activity of Seaweed Antioxidants in vivo.
Airanthi Widjaja-Adhi, Masashi Hosokawa, Kazuo Miyashita, Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
Brown seaweeds (BS) contain high level of antioxidants, namely, fucoxanthin (Fx) and phlorotannins (Pr). Although many researchers have reported Pr as main antioxidants of BS, the present study found the importance of Fx, as antioxidant in vivo. In vitro system, we found that the activity of BS extracts were dependent on the composition of both Pr and Fx. The synergy in a liposome system was also observed. On the other hand, the antioxidant effectiveness of BS extracts was only found in mouse fed Fx rich, while little was observed in the mouse fed Pr rich without Fx. The different effect between both antioxidants would be due to the lower bioavailability of Pr. In this research, we found a significant decrease in hepatic-cholesterol and triacylglycerol of mouse fed BS lipids containing Fx and omega-3. The amount of hepatic-DHA was also significantly increased in the mouse fed Fx rich BS-lipids. However, the increase level of DHA was lower in the mouse fed BS-lipids containing low level of Fx, even though the dietary lipids added by these lipids contained higher amount of omega-3 (10.9%) than those (7.4-7.7%) added by Fx rich BS-lipids. We have reported the increase in the bioconversion of α-linolenic acid to DHA by Fx feeding. Present study suggests that promotion effect of Fx on DHA synthesis more affected the hepatic DHA level than total omega-3 contents of dietary lipids.
Oxidation of Omega-3 Enriched Fish Oil for Animal Feeding Applications.
J.H. Lee1, B Kouakou1, G Kannan1, B.J. Min2, 1Fort Valley State University, Fort Valley, GA 31088, USA , 2Tuskegee University, Tuskegee, AL 36088, USA
Omgea-3 polyunsaturated fatty acids in fish oils such as eicosapentanoic (EPA) and docosahexanoic (DHA) acids, have received increasing attention for their nutritional aspects. However, DHA and EPA are extremely susceptible to oxidative deterioration. Although many studies have been conducted on oxidation of fish oil, limited information is available on oxidative stability of fish oil for animal feeding. The stability of omega-3 enriched fish oil used for animal feeding applications (Virginia Prime GoldTM, Houston, TX) was studied during storage at 80°C with aeration for 10 days. The accelerated oxidative stability of the fish oil was monitored by analyses of color (CIE, L*a*b*) and peroxide values (PV), as well as fatty acid and oxidized volatile compounds using methylation with gas chromatography (GC) and solid phase microextraction (SPME) with GC-mass spectrometry (MS), respectively. Lightness (L* value) and redness (a* value) of fish oil decreased (P < 0.05) progressively with the storage time, but yellowness (b* value) increased (P < 0.05) until day 6. The PV of oil significantly increased within the first 2 days. Of 13 identified oxidized volatile compounds, hexanal, 2-nonenal, 2,4-decadienal, and 2,4, heptadienal may be used as the indicator of omega-3 enriched fish oil degradation during the accelerated oxidative storage.
Carbon Dioxide Blanketing Enhances the Frying Stability of Oils and Improves the Nutritional Quality of Fried Foods.
F. Aladedunye1, B. Matthäus2, R. Przybylski1, 1University of Lethbridge, Lethbridge, Alberta, Canada, 2Max Rubner-Institute, Münster, Germany
The effect of carbon dioxide blanketing (CDB) on the frying performance of canola oil was evaluated. For 7 h daily and for 7 days, French fries were fried in canola oil at 185±5oC without and with CDB. The extent of thermo-oxidative alterations in the oil was assessed by analysis of total polar compounds (TPC), anisidine value (AV), color component formation and changes in composition of fatty acids and tocopherols. Furthermore, 4-hydroxynonenal (HNE) and acrylamide, the two most toxic compounds formed during high temperature processing of food, were quantified in the fries. Compared to standard frying conditions (SFC), the amount of TPC and AV were reduced by 54 and 65%, respectively when the frying was conducted under CDB. At the end of the frying period, the reduction in polyunsaturated fatty acids was 3.8 and 12.7% when frying under CDB and SFC, respectively. The average rates of tocopherol disappearance were 82 and 17 µg/g per frying day during SFC and CDB, respectively. Consistently, fries prepared under SFC contained significantly higher amounts of HNE and acrylamide than those prepared under CDB. Thus, CDB is an effective way to enhance the frying stability of oils and improve the nutritional quality of fried foods.
The Relation between Peroxide Value and Flavor Deterioration in Peanut Oil during Storage.
Fan Jing, Jiang Yuanrong, Li Xinghan, Xiang Chuanwan, Wilmar Biotechnology R&D Center, Shanghai City, China
Peroxide value (PV) is one of the most popular indicators being employed in oil industry to access the product quality. However, limited source of research could be found to provide an elaborate explanation of the relation between the PV and the oil flavor deterioration. In this study, the flavor stability of the aromatic peanut oil with different initial PVs was examined based on the sensory evaluation and the amount of volatile compounds generated. 5 samples obtained from the same oil stock were stored open to the air for different time periods and, consequently, different PVs were developed. The results showed that, if stored in the dark and at ambient temperature, the 5 samples were detected with no significant off-flavor by sensory evaluation. After the pretreatment of oxygen removal by vacuum, the samples of various PVs were insulated from the contact of oxygen and heated at 63oC. While the PVs of all the samples decreased upon heating, the samples with relatively high initial PVs underwent flavor deterioration faster than those with low PVs. It was noticed that the amount of volatile compounds formed was proportional to the change of PV but not to the initial PVs. In addition, the sample with a PV change of lower than 1.4mmol/kg was not subjected to flavor deterioration detectable by sensory.
Effect of BHT on the Biodegradability of Glyceryl Trilinoleate.
D.A. Salam1, M.T. Suidan1, A.D. Venosa2, 1School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, Cincinnati, OH, USA, 2USEPA, Office of Research and Development, National Risk Management Research Laboratory, Cincinnati, OH, USA
Glyceryl trilinoleate, the most susceptible triglyceride to auto-oxidation, was used as a model system to determine the effect of butylated-hydroxytoluene (BHT) on vegetable oils biodegradability and toxicity in contaminated aquatic environments. Respirometric experiments were conducted for the aerobic biodegradation of glyceryl trilinoleate at a loading of 333 gal acre-1 . BHT was supplemented to the oil at different concentrations ranging from 0 to 800 ppm (no BHT added, 50, 100, 200, 400, and 800). Completely mixed conditions were simulated in 250 mL microcosms. Three replicate samples and three abiotic blanks were run per each BHT concentration. Competition between polymerization and biodegradation was observed. Except for the abiotic blanks with no BHT added, no toxicity was detected in the liquid phase after 19 weeks of incubation.
Phospholipid Autoxidation in Organic and Water Media.
E.A. Mengele, D.A. Krugovov, O.T. Kasaikina, Semenov Institute of Chemical Physics RAS, Moscow, Russia
Lipid oxidation and phospholipid transformation have always been serious concerns of food quality and consumers health. Phospholipids are natural surfactants which are widely used in food, cosmetic and drug production both on oil and water base. Egg lecithin (Fluka) (LH) autoxidation by O2 was studied as a model reaction of phospholipids oxidation in organic and water media. Autoxidation was carried out in organic medium at 37-70C and at 30-45C in water solution. The formation of reverse micelles in organic solvents and liposomes in water solutions was studied by light scattering. The rates of lecithin oxidation at the same mass concentration, initiation rate and temperature were found to be higher in organic media. The rate of lecithin oxidation in the presence of Ca2+increases in organic media and it decreases in water environment. Both reverse micelles and liposomes are destroyed under these conditions.Effects of lecithin and lecithin + Ca2+ on the lipid hydroperoxide (LOOH) decomposition were investigated as well. Interaction of zwitterionic lecithin with Ca2+ results in the formation of a cationic surfactant which catalyzes LOOH decomposition into free radicals, so the initiation rate increases.
Optimization of Oil Oxidation by Response Surface Methodology and the Application of this Model to Evaluate Antioxidants.
G.F. Branco, I.A. Castro, University of São Paulo, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, São Paulo, SP, Brazil
The oxidative stability of oils is a complex process influenced by several factors, becoming difficult the evaluation of the antioxidant effect of new compounds for further utilization in food systems. Thus, the objective of this study was to apply a factorial design to obtain the combination of factors that maximizes the formation of primary and secondary products of oil oxidation, and use this model to evaluate the antioxidant activity of different compounds. Initially, temperature, Fe2+ and ascorbyl palmitate were evaluated in a full-factorial design (23) using flaxseed oil stripped of its minor components. Afterward, another full-factorial design (32) was carried out, keeping the temperature fixed at 40oC and varying the concentrations of Fe2+ and ascorbyl palmitate. The validated optimized oxidation model was obtained through response surface methodology by adding 1.47 mmol/L of Fe2+ and 1.54 mmol/L of ascorbyl palmitate to the stripped flaxseed oil kept at 40oC for 8 days. Antioxidant activity of six compounds was evaluated using this model. All antioxidant samples were statistically different (p<0.001) at 200 ppm concentration, which demonstrates the efficiency of the optimized model for the evaluation of the antioxidant action of natural and artificial compounds.
Investigation of Factors Affecting Oxidation of Frying Oils.
X. Tian, K.M. Schaich, Rutgers - The State University of New Jersey, New Brunswick, NJ, USA
Lipid oxidation processes and factors affecting oxidation at high temperatures were investigated. Oxidation characteristics of fresh, stripped and steady-state oils provided baselines for determining changes in kinetics and product pathways induced by metals, phospholipids, oxygen, water, free fatty acids, and pre-formed oxidation products. Catalytic factors tested individually and in combination revealed synergistic effects. Conjugated dienes, peroxide values, and aldehydes were followed throughout the heating period; volatiles released during heating were trapped and analyzed by GC-MS. Oxidation pathways show a major change in mechanism above 150C, where thermal reactions become major initiators. Appearance of short chain aldehydes as the major early product is consistent with thermal scission of acyl chains followed by addition of oxygen and dismutation of the resulting terminal peroxides. These aldehydes oxidized to carboxylic acids, accounting for most free fatty acids in dry oils. Conjugated dienes remained low, indicating minor involvement of autoxidation chains. Pre-oxidation levels in oils, oxygen concentrations in the headspace, and catalytic factors had little effect on initial oxidation rates but strongly altered secondary oxidation stages. Results will be integrated to develop a more accurate picture of thermal degradation of highly unsaturated oils.
Evaluation of Oxidative and Sensory Characteristics of Refined Soybean Oil under Different Purity Nitrogen Atmosphere.
Andréa Dal–Bó1, Rogério Machado2, Maria José Deschamps1, 1Bunge Brasil S.A., Gaspar, Santa Catarina, Brazil, 2Bunge Management Systems Inc., Gaspar, Santa Catarina, Brazil
One of the factors responsible for the oxidation of oils is the oxygen present in the headspace which attacks double bonds to initially form hydroperoxides.To reduce this effect, nitrogen is added to the oil.The aim of this study was to evaluate the influence of nitrogen purity on the oxidation of SBO.PET bottles were filled with SBO and sparged with nitrogen of different purities: 99.99, 99.9 and 99.5%.The samples were evaluated during 4 months for the formation of primary and secondary compounds of oxidation (peroxide (PV) and anisidine values (AV)) and sensory characteristics (consumers rating rancid flavor).After 4 months SBO bottled under 99.99, 99.9 and 99.5% nitrogen atmosphere presented the following results for PV: 2,56; 2,63 and 2,69 meq/kg, respectively.Sensory analysis based on AOCS flavor grading scale, rated 99.99 and 99.9% nitrogen purity as 6, and 5 for 99.5%.The statistical analysis of PV and sensory results showed a faster oil degradation under a 99.5% atmosphere, while SBO with 99.99 and 99.9% nitrogen purity presented similar performance.AV results showed no significant differences among all nitrogen purities.Based on these results, the 99.99 and 99.9% purity nitrogen exhibited the best results for oxidative and sensory characteristics of the nitrogen-sparged PET-bottled SBO, enabling the reduction up to 99.9% purity.
Alaskan Salmon Oil Composition Monitored for One Harvest Season.
J. Stine1, T. Wu1, A. Phillips2, U. Taraga2, R. Lyons2, D. Chase2, P. Bechtel1, 1USDA, ARS, Kodiak, AK, USA, 2Texas Tech University, Lubbock, TX, USA
Commercial fish oils are used as nutritional ingredients in foods and feeds. Research is needed to understand changes in quality and composition of commercial fish oils extracted at different harvest times. The purpose of this study was to characterize the quality and composition of commercially produced oils obtained over the commercial harvest salmon season in Alaska. Samples of commercial salmon oils were obtained twice weekly from two processing plants over the peak harvest period. The samples contained large amounts of w-3 fatty acids (30.3%), made up primarily of eicosapentaenoic acid (EPA, 20:5w3) (9.7%) and docosahexaenoic acid (DHA, 22:6w3) (10.6%). The most abundant fatty acids were palmitic acid (16:0), oleic acid (18:1n9c) and cetoleic acid (22:1n11). Oil samples were analyzed for contaminant PCBs and organochlorine pesticides and all samples were below detection levels. Analysis of fat soluble vitamins identified low vitamin D levels (< 2ug/g), and large variations in the retinol and alpha tocophercol levels (RSD > .3). All oils had low TBARS and FFA values. Results indicated that oils obtained throughout the commercial harvest period of Alaska wild caught salmon were of high quality with a relatively constant DHA and EPA content.
Performance Evaluation of Refined Soybean, Cottonseed and Rice Bran Oils in Discontinuous Deep Frying of Potato Strips.
Andréa Dal–Bó1, Rogério Machado2, Fernanda Emmert1, José Bérgamo1, Alessandro Borchartt1, Vanessa Zanuto1, 1Bunge Brasil S.A., Gaspar, Santa Catarina, Brazil, 2Bunge Management Systems Inc., Gaspar, Santa Catarina, Brazil
Frying is a cooking process that enhances food flavor, color and texture.This study aims to evaluate the performance of refined soybean (SBO), cottonseed (CSO) and rice bran (RBO) oils in a discontinuous deep frying process.30 batches of potato strips were fried at 180°C in a Frymaster fryer over 5 consecutive days, 6 hours/day, with replenishment of fresh oil at the end of each day.Physical-chemical properties of the oils (acid and anisidine values, specific extinction at 232 and 268nm, color, polar compounds), sensory characteristics of the fried potato strips, and the need for replacement of each oil/day were evaluated.The statistical analysis of physical-chemical results showed that the oxidative performance for SBO was lower than CSO and RBO.For CSO and RBO, the results were similar.The 3 oils tested remained within the limits for polar compounds (25%) and acid value (between 1-1.5%) until the 5th day of frying.Regarding sensory analysis, a significant difference was perceived between potatoes fried with SBO and RBO only on the 1st day of frying.For CSO and RBO, sensory panelists noticed a significant difference only on the 5th day.Considering the average replenishment (for 5 days), RBO showed the best result with 2% less oil required when compared to SBO and CSO.These last two had similar results for replenishment.