Science highlights from a cancelled 2020 AM&E
By Rebecca Guenard
- The 2020 AOCS Annual Meeting & Expo would have been held in Montréal, Canada, on April 26–29. However, on March 20th the governing board made the difficult decision to cancel the meeting to avoid the risk of spreading the novel coronavirus.
- AOCS received over 500 abstracts for oral and poster presentations on impactful science in the fats, oils, and related industries before the meeting was cancelled.
- This article summarizes a few of the interesting technical presentations that would have been given at the meeting. More than 200 technical and poster presentations will be made available during the Virtual 2020 AOCS Annual Meeting & Expo, June 29–July 3, 2020, and can be accessed until 2021.
We were all looking forward to the AOCS Annual Meeting & Expo in Montréal, Québec, Canada, April 26–29, but a global pandemic forced us to adjust our plans. In January, reports of respiratory infections caused by a novel virus spreading across Asia, into Europe, and then to the west coast of North America had everyone on edge. As mid-March arrived, it was obvious that slowing the spread of the virus required eliminating its means of transmission. People needed to stay away from each other, and the AOCS governing board made the painful decision that—as much as we relish our time together—the annual meeting would be cancelled.
The AOCS staff shifted gears immediately. From our newly occupied home offices, we considered ways to provide resources to AOCS members and help them experience the meeting as much as possible. We published the @home digest containing research interests, learning opportunities, and career advice. We hosted Executive Steering Committee meetings over Zoom for AOCS’ 10 Divisions to transfer leadership between incoming and outgoing chairs and plan for the upcoming year. And, we acquired a digital platform to host the 2020 Annual Meeting online.
Though our meeting was not in person, it was still an opportunity to share stimulating science. Unfortunately, there are not enough pages in Inform for a complete review of everything that was discussed this year. Instead, we offer a brief selection of some of the interesting research that was part of the program.
Displacing petroleum heating oil with biodiesel, Thomas Butcher and Ryan Kerr, National Oilheat Research Alliance, United States, Industrial Oil Products
Last September, the heating oil industry made a resolution to transition to a renewable energy future. The traditionally petroleum-based industry set an ambitious goal to reduce greenhouse gas emissions to 1990 levels. They would start by increasing the amount of biodiesel in heating oil to 20% within the next three years, then to 50% by 2030, with the goal of net zero emissions by 2050.
The NORA (National Oilheat Research Alliance) supports the heating oil industry by conducting research on the technical barriers that may inhibit the achievement of these goals. Biodiesel is an ester, an oxygenated fuel, that will have different chemistry compared to petroleum, a hydrocarbon. NORA has studied the compatibility of biodiesel fuels with existing oil heating system components, including seal materials, metal piping, and outdoor tanks.
The seals connecting pumps and filters to the rest of a heating oil system are commonly made from a nitrile-based elastomer. NORA has evaluated whether exposure to biodiesel could degrade or somehow compromise such seals. “We do a lot of testing on how different fuels will swell the common elastomers we have in the industry,” says Ryan Kerr, NORA lab team member. He immersed the elastomer seals in the fuel and found that in biodiesel it swells to anywhere from six to 20% of its original size. Whereas, with petroleum heating oil, the seals swelled a maximum of 8%. Though the swell value of the elastomer in biodiesel falls below the current allowed standard, some researchers are concerned the fuel could degrade elastomer seals more significantly if it were to break down into organic acids, leading to pump or filter failure. Kerr says that some equipment has started to be manufactured out of the synthetic rubber and fluoropolymer elastomer, Viton, instead of nitrile, because it is more compatible with biodiesel. But Thomas Butcher, director of NORA Laboratories, says it is difficult to generalize all nitrile elastomers as problematic in biodiesel applications, since acrylonitrile percentages vary, as do additive and filler amounts. “The story with the elastomers is that people can use, and are commonly using, biodiesel blends with traditional equipment,” Butcher explains. “But equipment manufacturers would really like to transition to better elastomers in the future, and that transition has started to occur.”
Copper is the primary metal used in fuel systems across the United States, because of its malleability. NORA sought to determine if biodiesel reacts with it. “People are concerned about the stability of biodiesel,” says Butcher. “But petroleum hydrocarbons also have stability issues.”
The Rancimat test is a common tool to test the degradation of an aging fuel. Kerr exposed samples of biodiesel and petroleum diesel to copper before performing the Rancimat test. The Rancimat induction period decreased rapidly, indicating instability in both fuels after copper exposure. The fuels were also tested for long-term copper storage by incubation above 100°F which is equivalent to a month of standard temperature fuel storage.
“We saw a lot of polymers forming in the fuels exposed to a copper surface,” says Kerr. “There were particulates floating around in these fuels.” However, after testing multiple biodiesel fuels, he found that there was less degradation than observed for petroleum. He speculates this is due to the additives incorporated into commercial biodiesel fuels. Kerr says he also tested fuel sitting in a sealed copper line. Without the presence of oxygen, the fuel remained stable. “Overall, we did not find any real-world problems with biodiesel that would require getting rid of all our copper pipe,” says Kerr. “Our big caution is if fuel has been exposed to copper, the Rancimat test results will be affected,” Butcher adds.
One problem that remains to be addressed is biodiesel’s cloud point, which can range from 30 to 55°F for pure biodiesel, depending on the source of vegetable oil. When heating oil tanks are stored outside, biodiesel fuel would not remain liquid during cold winter months when it is needed most. Kerr says they have tested low-voltage tank heaters and tank covers to insulate the fuel from the outside air. The best solution would be to move the storage tank indoors, but that may not be possible depending on the size of the house. Butcher says there may be a chemical solution to this problem. When the biodiesel is composed of unsaturated molecules, cold flow properties improve, but the fuel is less stable. Butcher suggests that the industry needs to start considering additives for pure biodiesel that modify its properties to make it a stable liquid at low temperature. Kerr agrees but adds, “We are looking at these non-chemical solutions because right now we have not figured out a molecular one. But maybe in the future that will happen.”
Kerr maintains that all the research conducted by NORA shows that biodiesel and petroleum diesel are similar. “There are notable differences, and they will present challenges as we move forward,” he says. “But from what we can see now, none of these challenges are unsurpassable.” Butcher concludes that the politics and economics of fuels are unknown, but their sole focus at NORA is to ensure there are no technical barriers to using 100% biodiesel as heating oil by 2050.
Research and development for novel pressure sensitive adhesives from vegetable oils, Kaichang, Li , Oregon State University, USA, Biotechnology
In 2004, Kaichang Li, chemical engineering professor at Oregon State University, in Corvallis, Oregon, commercialized a new wood adhesive made from soybean meal. The protein and carbohydrates from the meal were synthesized into an adhesive for making things like plywood and particleboard. Unlike conventional wood adhesives, the new soybean flour-based products do not contain formaldehyde or other toxic chemicals. Over the past decade, Li has worked with soybean oil in an effort to make a pressure sensitive adhesive for eco-safe tapes and labels, which he hopes will gain as much commercial success as his wood adhesive.
Pressure sensitive adhesives (PSAs) represent a multibillion-dollar business. The sticky substance is needed for bandages, notes, and stamps, with a significant economic contribution from the online retail sector. Countless packages shipped around the world everyday require labels and seals, currently produced using petrochemicals.
“I do research on how to develop environmentally friendly products from renewable materials,” says Li. “We saw that the existing PSAs were not biodegradable, and we wanted to find a replacement.”
His team has discovered how to make novel polyesters from a variety of soybean oil’s fatty acids. When oleic acid is epoxidized, for example, the resulting monomer contains a carboxylic acid group and an epoxy group. Polymerizing the epoxidized oleic acid generates a new type of polyester ideal for PSAs. In addition, epoxidized soybean oils can contain multiple epoxy groups, and dimers of fatty acids can contain multiple carboxylic acid groups. The relative content of the epoxy and carboxylic acid groups determines what type of adhesive can be made. For Band-Aids® and Post-it® notes, you do not want the adhesive to be too sticky, says Li. But for other uses, a strong adhesive is necessary.
Li’s teams investigated the relationship between the chemical structures of soybean oil derivatives and PSA properties. They characterized molecular structure, thermal stability, and viscoelastic properties, as well as peel strength, shear strength, tack, and aging stability of the PSAs. “We are now able to formulate adhesives for different requirements,” he says.
The development of the green adhesives also improves upon current PSA manufacturing practices. Tape and label manufacturers convert a petrochemical-based monomer into a polymer emulsion that is coated onto a film and dried in long tunnels to evaporate the water. Li’s adhesive avoids this energy-intensive process that requires expensive equipment. He incorporated the soybean oil polymer into a stable resin that can be shipped directly to a production line. He says, once the resin is coated onto a backing the adhesive can be cured in about one second of exposure to ultra-violet light.
“Our adhesive is less expensive than the petrochemical-base PSAs,” says Li, since they do not require a large capital investment for equipment and the excessive energy costs to run them. He is hopeful that the vegetable oil-based adhesives will be commercialized soon.
Development of a novel test strip which demonstrates longer fry life of high-oleic oils, Susan Knowlton and John Everard, Corteva Agriscience; Enrique Martinez, Food Quality Testing Corp, USA, Lipid Oxidation and Quality
About five years ago, Susan Knowlton, senior research manager at Corteva Agriscience, was looking for an easier way to measure the end of an oil’s fry life when she met Enrique Martinez, a physical organic chemist interested in food chemistry. Knowlton and Martinez talked about producing a quick, inexpensive test for food industry professionals to determine the quality of their frying oil.
“When you talk to people in the industry, they always say they would love to have a way to objectively determine when it is time to change fry oils,” Knowlton, says.
Restaurants want to avoid rancid oil that has polymerized in the fryer, but despite the existence of a few commercially available tests, most prefer arbitrary means to determine if their oil is spent. Whether or not a staff member can see a submerged ladle, for example, or a habitual Sunday oil change regardless of its appearance. Knowlton says there should be a test that serves the needs of the market.
According to regulations in many European Union countries, fry oil must be changed when the concentration of polar compounds—a product of triglyceride decomposition—has reached 25% by volume. Since the EU decided to measure oil quality by polar compound content, Knowlton and Martinez did too. Their team spent several years in the lab developing a test strip that changes color according to the total polar compound concentration in an oil. The strip was tested extensively with controls of purified fatty acids, and mono-, di-, and triglycerides which correlated with a specific color change. They validated their test strip for increasing concentrations of total polar compounds using the AOCS official method as well as modeling with FT-NIR. The prototype and the bench measurements had good correlation, and testing moved to a low-use kitchen. The team set up an experiment in the Corteva cafeteria. Successful measurement there evolved into plans to test the strips in the cafeterias of a large university. Unfortunately, the university closed to prevent the spread of the novel coronavirus, interrupting the study which will resume once the university dining hall reopens. Prior to the outbreak, Food Quality Testing was planning to make the test strips available for purchase this Spring.
“Once we get it commercialized I think it will be very successful,” Knowlton, says. “And it will benefit the high-oleic oils space.”
With fewer polyunsaturated fatty acids than commodity seed oils, high-oleics represent a more stable product that does not oxidize as easily at high temperatures. They are more expensive than other vegetable oils, but Knowlton says the payback comes in the form of better quality food from an oil with a longer frying life. In the real-world of a functioning restaurant, fry oil life can now be quantified with a test stripe, and high-oleic’s benefit to kitchen operators will be apparent. “People will see that they get another week out of their high-oleic oil, and it is worth the extra cost,” says Knowlton.
Lipid bioaccessibility of cooked meat using the dynamic in-vitro gastrointestinal TIM-1 model, Michael, Rogers, University of Guelph, Canada, Edible Applications Technology
Associate Professor of Food Science Michael Rogers started his research career curious about how human evolution changed with food preparation. He found a published paper that described physical changes—bigger heads and smaller teeth—that accompanied the onset of cooking over fire in the Northern Hemisphere. The paper provoked him to ask a question: Could he measure a genetic change based on diet? There is evidence of such evolutionary changes present today. Tribes living in the African plains who exist on mostly grains have genes that signal more production of salivary amylase, an enzyme that catalyzes the digestion of dietary starch. Whereas a fishing tribe that eats mostly fish protein has a genetic code that produces less of the enzyme.
Rogers says that today’s consumers get more calories from ultra-processed than from whole foods, and he wanted to study if this change in the composition of the foods we eat could be associated with current evolutionary factors, like increased chronic diseases. “Food particles vary in size and elasticity which regulate how fast enzymes can breakdown and absorb the macro and micronutrients of the substrates,” says Rogers. He wanted to test how the material properties of food affect the release of their nutrients when the food’s composition is identical. In other words, given the same amount of fat, would there be differences in the way a food was digested based on its physical state?
“If a steak is cooked rare, will it digest the same as one that is well-done?” asked Rogers. The steak will have the same amount of protein and calories from fat regardless of how it is cooked, he says. But did the digestion rate depend on the robustness of the food’s structural network?
To perform these digestion kinetics studies, Rogers and his student, Elizabeth West, used an in vitro model originally designed for pharmaceutical trials, known as the TIM-1 gastrointestinal system. TIM-1 is a dynamic system that simulates peristaltic contractions triggering the release of digestive enzymes and fluids as food transitions through the stomach into the intestines. Roger’s team cooked the meat sous-vide style, in a vacuum-sealed bag inside a water bath at low temperature to different degrees of doneness and found that lipid digestion varied with cooking temperature. The lipemic index for a well-done steak is not the same as a rare steak and, though you absorb the fat for both, it takes longer for the fat from a rare steak to enter the blood stream. “The chemistry of a food’s lipids is not as significant to the lipemic index as the physical structure of that food,” he says. Just like the glycemic index measures blood sugar, the lipemic index indicates the amount of fat in the blood, and rapid increases correlate with detrimental health affects like increased inflammation.
Rogers says he would like to use this data to evaluate whether scientists can design a processed food to have a similar metabolic response to a whole food. Food scientists have devoted many research hours to engineering the stability, palatability, and functionality of foods, he says. “We moved nutritional profile to the backseat. Now it’s time to focus on mimicking the biological structures in whole foods to impose digestive barriers in processed foods and slow down the process.”
Consumers are becoming convinced that a cell-cultured meat is nutritionally equivalent to animal- derived meat, and that is just not true, says Rogers. “From a digestive prospective, a Beyond Burger behaves more like a confectionary product than a whole food meat,” he says. “That is problematic, especially when we are designing a food to replace something that is nutritionally valuable.”
Diet has become the determinant of life expectancy, according to Rogers. “We are seeing that people who consume more that 50% of their diet from ultra-processed foods have a higher rate of all-cause mortality across all ages,” he says. “Our diet today is actually limiting life expectancy.” As climate change continues to affect agriculture, he predicts that the cost of whole foods will increase disproportionally to processed foods. If these lower cost foods will be consumed by more people, it is important to consider them as a complete system and how that system behaves as a material in the stomach, says Rogers. He hopes to see more food science applied to achieving the same glycemic and lipemic from processed foods that result from eating whole foods.
Realtime process control using spectroscopic techniques; Jonathon Speed, Keit Spectrometers, United Kingdom, Analytical
Originally, the physicists at Keit Spectrometers designed their instruments to analyze the Martian atmosphere. They were lightweight and durable enough to withstand the trip into space. The spectrometer measures molecular vibrations, but—unlike traditional instruments—it was designed to endure vibrations from surrounding equipment without their interference. Unfortunately, the instrument was ready to make the voyage a week after the rocket launched. So, Keit turned their attention to potential terrestrial uses.
Product and Applications Manager Jonathon Speed determined that the instrument could function as an online, real-time analyzer for refining processes. This type of technology has been used by the chemical and pharmaceutical industries to streamline manufacturing and reduce costs, says Speed. He believes his analyzer can do the same for edible oil refining.
“Our analyzer can measure the total free fatty acids in the oil, along with a profile of the types of fatty acids that are present,” says Speed. He lists fatty acid methyl esters, water, free glycerol, soaps, and hydratable and non-hydratable lipids as a few examples of the compounds the analyzer can measure simultaneously.
According to Speed, the analyzer can be operated in feed-forward and feed-back functions and used to adjust the refining process without stopping production. He says that placing the analyzer at the start of the process to measure crude oil composition means more efficient accounting of refining agents. “You know exactly how much phosphoric acid is needed, because you can measure the concentration of hydratable and non-hydratable lipids,” says Speed. “And you also have a value for your free fatty acids to get the caustic dosing exact.” However, since no chemical reaction is 100%, he suggests installing the analyzer further along the process to make fine-tuned process adjustments. For example, he says that manufacturers can reduce water use when at the separator stage of the process by analyzing soap content after caustic addition.
Speed acknowledges that reputation of online vibrational spectroscopy measurements was tainted by the unfulfilled promises of NIR analyzers. Those analyzers turned out to be inaccurate, in part, because they required a level of expertise in theoretical chemistry on the part of the operator. Near-infrared analysis requires advanced mathematical models for calibration, since the frequencies it measures are overlapping vibrational overtones that are notoriously difficult to interpret. The Keit spectrometer works in the mid-IR, measuring unique molecular vibrations that undergo pronounced frequency shifts as the oils are processed. This, Speed says, simplifies the analysis. The NIR analyzer became popular first, because, at the time, there was not an FT-IR that could function in a manufacturing environment due to the inherent vibrations associated with the equipment. Speed says the instrument has since been revamped and functions trouble-free in an edible-oil process.
Rebecca Guenard is the associate editor of INFORM at AOCS. She can be contacted at firstname.lastname@example.org.
Virtual 2020 AOCS Annual Meeting & Expo
You can learn more by attending the Virtual 2020 AOCS Annual Meeting & Expo, June 29–July 3, 2020. The virtual meeting is free to all and includes more than 200 technical and poster presentations, including presentations on three of the topics summarized in this article. Content from the meeting will be available on demand until 2021.