Location: Functional Foods Research
2023 Annual Report
Objectives
Objective 1. Stabilize sensitive and bioactive food ingredients, improve shelf-life, and reduce food waste with optimized natural antioxidants and plant extracts.
Sub-Objective 1.A. Evaluate antioxidant activity of combinations of antioxidants in frying oils and fried foods.
Sub-objective 1.B. Evaluate antioxidants or natural antioxidant extracts for protection of polyunsaturated and omega-3 oils and bioactive lipids and to extend shelf-life of whole foods and food ingredients.
Objective 2. Enable oleogel applications to reduce saturated fats in foods.
Sub-Objective 2.A. Investigate and optimize the physical and sensory properties as well as the oxidative stability of edible oleogels.
Sub-objective 2.B. Evaluate interesterified natural waxes, waxes with vegetable oils, fatty alcohols or fatty acids, as potential new oleogelators.
Objective 3. Improve commercial value and sustainable food production through recovery of healthful bioactive ingredients from food processing by-products or waste.
Approach
Approximately 30% of the food supply in the United States is wasted and the worldwide problem is even larger. This waste represents a large strain on the environment and on the entire food production enterprise. According to the Food and Drug Administration (FDA), about 20% of the food waste in the United States is due to confusion about the meaning and safety of foods labeled with “best before” and “use by” dates. This means that extending shelf-stability of foods can have an impact in reducing food waste. There is also concern about the healthfulness of processed foods, including the high content of saturated fats, which consumers are advised to limit in the diet. However, reducing the saturated fat content of foods by substituting with healthier fats can influence product texture and mouthfeel, as well as the oxidative stability and shelf-life. The research of the next five years will enable the commercial development of natural antioxidants needed to improve the oxidative stability and shelf-life of foods formulated with a lower saturated fat content. Antioxidants will improve the stability of frying oils, fried foods, and high-value foods such as nuts and protein replacement bars. Oleogels will be developed with improved physical and melting properties for margarines and shortenings and other food applications that require hard fats and will have lower amounts of saturated fats and zero trans fats. New value-added ingredients such as antioxidants and bioactive lipids will be mined and characterized from low-value agricultural inputs. This research, together with complimentary technology and policy development strategies, will contribute to efforts to reduce food waste and improve the healthfulness of the food supply.
Progress Report
Sub-objective 1.A is to evaluate the antioxidant activity of combinations of antioxidants in frying oil and fried foods. The overall goal is to develop synergistic antioxidant combinations that can be used to improve frying oil life. In support of Sub-objective 1.A. (Publication 1, Accomplishment 1), sodium and potassium carbonates and bicarbonates, which are common food ingredients, were shown to have strong antioxidant activity in soybean oil and several other oils at frying temperature, which was verified in frying studies. The bicarbonates were then proven to enhance and preserve tocopherols (naturally present antioxidant and vitamin E components) in vegetable oils. In addition, the carbonates and bicarbonates were further shown to have either additive or synergistic interactions with other commercial natural antioxidants such as rosemary extract, epigallocatechin gallate (from green tea extracts), ascorbic acid (vitamin C), and ascorbyl palmitate (a vitamin C analog). In addition to the publication, this research was presented at the 2023 American Oil Chemists’ Society (AOCS) Annual Meeting. Additional progress towards Sub-objective 1.A. was to evaluate the effect of corn fiber extracts (also related to Objective 3) on stability of soybean oil during frying of tortilla chips. While the corn fiber extracts were shown to be excellent antioxidants in the frying oils and to slow degradation of soybean oil tocopherols during frying, they did not improve the activity of rosemary extracts during testing. This work is complete and has been presented at the American Oil Chemists Society Annual Meeting and a manuscript is in progress.
Sub-objective 1.B is to evaluate antioxidants or natural antioxidants for protection of polyunsaturated and omega-3 oils and bioactive lipids and to extend shelf-life of whole foods and food ingredients. Due to some setbacks in personnel, equipment, and administrative issues for sensory analysis, we chose to focus on other goals for this objective, while sensory testing will be delayed until these issues are resolved. This fiscal year, we focused on methods to screen antioxidants for shelf-life improvement, and developing a new method based on nuclear magnetic resonance (NMR) for quantitative analysis of lipid aldehydes, peroxides, and epoxides that form during lipid oxidation. Shelf-life studies are time-consuming, because even accelerated studies at 55 degrees C may take a minimum of two weeks, depending on the inherent stability of the control food product. In the past fiscal year, we developed sweet potato chips (containing the bioactive lipid beta-carotene, which is pro-vitamin A) fried in canola oil as a model food product for studying shelf-life improvement by antioxidants. The results from this research were presented at the 2023 AOCS Annual Meeting and a manuscript is in progress. Recently, we focused on continuing to screen antioxidants for improving shelf-life of sweet potato chips, but also on testing whether using a rapid screening method could correlate with the shelf-life studies. Initial results indicate that the rapid screening method correlated well with accelerated shelf-life studies to at least give a positive indication that an antioxidant(s) added to frying oil during initial stages of frying could improve shelf-life. We plan to replicate these studies and test additional antioxidants and combinations during the next year. Methods for evaluating lipid oxidation during shelf-life studies in bulk oils and in food products call for analysis of both primary lipid oxidation products, such as lipid hydroperoxides, and secondary oxidation products, such as aldehydes, which are measured by a few methods, including headspace analysis of volatile aldehydes, and p-anisidine value, which is a non-specific measure of non-volatile aldehydes. These methods are old, require a lot of hazardous solvents as well as toxic compounds (p-anisidine), and are also very non-specific as well as not being very quantitative. Thus, we searched the literature and found a new method using band-selective NMR, and collaborated with the NMR research specialist at ARS in Peoria, Illinois, to adapt this technique for quantitation of 10 classes of hydroperoxides and aldehydes in frying oils as well as bulk oils and oils extracted from foods during shelf-life experiments, thereby reducing solvent and chemical use and waste and improving the quantitative and analytical results.
Sub-objective 2.A is to investigate and optimize the physical and sensory properties as well as the oxidative stability of edible oleogels. As progress towards this sub-objective (Publication 3, Accomplishment 2), the firmness of wax-based oleogels containing binary mixtures of beeswax and candelilla wax were shown to be significantly increased by substituting a small proportion of the mixtures with a third wax, sunflower wax. Although sunflower wax has a higher melting point than the other two waxes, this substitution did not alter the melting properties of the mixtures, therefore allowing for firmer oleogels that will not leave a waxy mouthfeel. In further progress towards Sub-objective 2.A, a study was conducted to evaluate the effect of the amount of oil unsaturation on oleogel physical properties. Nine oils with different levels of unsaturation are being tested with two waxes and a binary wax mixture. In addition, these oils are also being ‘stripped’ of everything except for the triacylglycerols, in order to also evaluate the effect of additional polar compounds in oil on oleogel physical properties. Sub-objective 2.B was to evaluate interesterified natural waxes, waxes with vegetable oils, fatty alcohols, or fatty acids, as potential new oleogelators. In progress towards this sub-objective, we have substantially completed a study on the physical properties of oleogels made with hydroxy fatty acids and hydroxy fatty acid methyl esters. With some additional testing, this study should be completed and submitted for publication in fiscal year 2023. Additional chemical interesterification of two waxes were attempted, but no promising oleogels were obtained from these results. Therefore, for the next steps, enzymatic interesterification (IE) between wax and palm oil or medium chain triglycerides (MCT) and chemical IE between wax and fatty alcohols or fatty acids are planned for the next fiscal year.
Objective 3 is to improve commercial value and sustainable food production through recovery of healthful bioactive ingredients from food processing by-products or waste. As progress towards this objective, we collaborated with ARS scientists in Peoria, Illinois, and Fort Pierce, Florida, to analyze tocopherols, peroxide value, p-anisidine value, and free fatty acids in oil extracted from waste seeds from the commercial sweet orange juicing process and used as a feedstock for biodiesel (Publication 7). We collaborated with pulse and flour researchers at ARS in Peoria, Illinois, to evaluate antioxidant activity of buckwheat flours subjected to different conditions of subcritical water flash release processing (Publication 4), and to evaluate the effect of processing on the headspace ‘beany’ odor compounds in pinto bean flours subjected to jet-cooking processing (Publication 6). We collaborated with scientists to develop a patented, low-odor and dust-reducing cat litter utilizing soybean hulls and soybean hull biochar (Publication 5). We also conducted extraction and analysis of silflower seed oils, a potential new drought-resistant perennial oilseed, and compared fatty acid composition, oil stability, tocopherols, and other oil quality factors, with native sunflower seed oil, to be presented at the 2023 Institute of Food Technologists (IFT) Annual Meeting, Chicago, Illinois.
Accomplishments
1. Baking soda may allow the use of healthier oils for fried foods. Ideally, restaurants would fry foods in healthy oils that are high in monounsaturated and polyunsaturated fats and low in saturated fats. Unfortunately, polyunsaturated fats quickly break down at the hot temperatures that are used in fryers. ARS researchers in Peoria, Illinois, demonstrated that sodium and potassium carbonates and bicarbonates, which are found in baking soda, baking powder, and are common ingredients in foods, acted as antioxidants when added (at 0.03% to 0.06%) to soybean oil, by protecting the polyunsaturated fatty acids from breaking down when heated at frying oil temperature (180 degrees C). Potassium carbonate and bicarbonate were found to perform the best, so they were further tested in five additional oils, including avocado oil, canola oil, corn oil, high-oleic soybean oil and olive oil. Breakdown of the polyunsaturated fats was reduced by 17% to 72% compared to the controls. In addition, potassium bicarbonate was evaluated in frying studies of potatoes at 0.06% in soybean oil and canola oil. It outperformed Tert-butylhydroquinone, the most commonly used synthetic antioxidant used in frying oils, which the food industry would like to replace with more natural ingredients. Thus, a common and well-known ingredient used in kitchens and by the food industry may extend the use of healthier oils for restaurant fried foods.
2. Optimizing the texture and melting properties for healthier fat substitutes. Current dietary recommendations to help prevent heart disease are to reduce saturated fats in the diet and replace them with vegetable oils that are higher in healthy monounsaturated and polyunsaturated fatty acids. However, replacing fats with oil is difficult to achieve in some food products because oil is not solid at room or refrigerated temperatures. Melting small amounts of natural waxes with vegetable oils form a solid called an oleogel. Oleogel properties can be changed by using different types and amounts of waxes, but if too much wax is used, it will leave a waxy taste and texture in the mouth. ARS researchers in Peoria, Illinois, discovered that by using certain mixtures of natural waxes that each have different properties, they could maximize the firmness of these oleogels at both room and refrigeration temperature without increasing the melting point. This means oleogels can be made without a waxy mouth feel and with texture and melting properties similar to traditional fats, so that they can be used to replace fats in food products to produce healthier foods. This information will be helpful for food companies as they strive to lower the saturated fat content in a variety of food products.
3. Bioactive lipids in distillers corn oil from U.S. ethanol plants. The United States produces 15 billion gallons of bioethanol per year from corn as the world's largest producer. Most bioethanol plants produce distillers corn oil (DCO) as a valuable co-product, which is used in animal feed and in biodiesel production, but also contains valuable bioactive lipids such as tocopherols, carotenoids, and phytosterols that could potentially be an additional high-value co-product. ARS researchers in Peoria, Illinois, and researchers with Trucent, in Dexter, Michigan, determined the range and variability in fatty acids, bioactive lipids, antioxidant activity, and oxidative stability of DCO collected from 30 bioethanol plants across the United States. DCO samples had higher oxidative stability than commercial corn oil and had extremely low variability in fatty acid composition. Phytosterols and phytosterol conjugates made up almost 2% of the DCO, and there was lower variability in content and composition between plants. The highest variability was in tocopherol, tocotrienol, and carotenoid content and composition, likely because these bioactive lipids are the most susceptible to heat and oxidation. This information will enable bioethanol plants to optimize their processing and extraction conditions to preserve these valuable bioactive lipids for potential valorization.
Review Publications
Moser, J.K., Hwang, H., Felker, F.C., Byars, J.A., Peterson, S.C. 2023. Increasing the firmness of wax-based oleogels using ternary mixtures of sunflower wax with beeswax:candelilla wax combinations. Journal of the American Oil Chemists' Society. 100(5):387-402. https://doi.org/10.1002/aocs.12679.
Hwang, H., Moser, J.K. 2022. Bicarbonates and carbonates as antioxidants in vegetable oils at frying temperatures. Journal of Food Science. 88(2):717-731. https://doi.org/10.1111/1750-3841.16442.
Moser, J.K., Hwang, H., Byars, J.A., Vaughn, S.F., Aurandt-Pilgrim, J., Kern, O. 2022. Variations in phytochemical content and composition in distillers corn oil from 30 U.S. ethanol plants. Industrial Crops and Products. 193. Article 116108. https://doi.org/10.1016/j.indcrop.2022.116108.
Plumier, B.M., Kenar, J.A., Felker, F.C., Moser, J.K., Singh, M., Byars, J.A., Liu, S.X. 2023. Effect of subcritical water flash release processing on buckwheat flour properties. Journal of the Science of Food and Agriculture. 103(4):2088-2097. https://doi.org/10.1002/jsfa.12399.
Vaughn, S.F., Liu, S.X., Berhow, M.A., Moser, J.K., Peterson, S.C., Selling, G.W., Hay, W.T., Jackson, M.A., Skory, C.D. 2023. Production of an odor-reducing, low-dust, clumping cat litter from soybean hulls and soybean hull biochar. Bioresource Technology Reports. 21. Article 101317. https://doi.org/10.1016/j.biteb.2022.101317.
Moser, B.R., Dorado, C., Bantchev, G.B., Winkler-Moser, J.K., Doll, K.M. 2023. Production and evaluation of biodiesel from sweet orange (Citrus sinensis) lipids extracted from waste seeds from the commercial orange juicing process. Fuel. 342. Article 127727. https://doi.org/10.1016/j.fuel.2023.127727.
Felker, F.C., Kenar, J.A., Singh, M., Moser, J.K., Byars, J.A. 2023. Comparison of raw and excess steam jet-cooked/drum-dried pinto bean flours and their effects on ground beef patties. Journal of Food Processing and Preservation. Article 5915625. https://doi.org/10.1155/2023/5915625.
