INFORM June 2026

12 INFORM JUNE 2026 , VOL. 37, NO. 6

Soy has traditionally reigned supreme in the alternative protein industry with pea protein following close behind. Both are key ingredients in many high-protein products, such as plant-based milk alternatives, meat substitutes, and protein bars. However, peas have some unique advantages. “In association with certain bacteria, pea has environmental benefits like helping to fix nitrogen, reducing the need for fertilizer,” says Fernanda F.G. Dias, assistant professor in the Department of Food Science and Nutrition at the University of Minnesota. “Peas also have good functional properties and lower allergenicity.” Despite their good qualities, soy and pea suffer from a problem that is common among plant-based proteins — they taste bad. Both have been described as “beany” and “green,” with peas also taking on an “earthy” or “chalky” off-flavor. “Consumers are more used to the flavor of animal proteins, but they want something more neutral from plant proteins,” says Wellington da Silva Oliveira, a postdoctoral fellow in Dias’s lab. For example, he explains that consumers do not expect a yogurt to taste beany, so they will perceive a yogurt with added pea protein as having a strong flavor. As a result, they may not enjoy it or purchase it again. To battle the funk, companies often mask these pea off flavors by adding pleasant tasting flavorings, and some

consumers add peanut butter or chocolate to protein products at home to make them more appetizing. INFORM recently examined how one research team is attempting to overcome soy’s off-flavor issue, and now, we have set our sights on pea. Researchers are investigating how pea protein extracts acquire their unpleasant taste, which could lead to new ways of removing it or mitigating it without added flavorings. Spoiler alert: It turns out that lipids are the main culprit when plant proteins taste a bit “off.” WHY ARE LIPIDS IN MY PROTEIN? The pea protein in high protein food products is typically obtained from yellow peas, which have slightly more protein per serving and less aroma than ready-to-eat green peas. To isolate protein from peas, the shells are removed by a milling process and then the flour is mixed with water, filtered and centrifuged to remove starch and fiber. In the isolation process, the protein undergoes an alkaline extraction, precipitation at its isoelectric point, pasteurization, and spray drying. “When we think about plant proteins, we do not think about the lipids that are there,” says Dias. “Pea protein isolation does not have a defatting step, so the oil is carried with the protein.” These lipids can become trapped or held

noncovalently within protein matrices. After oxidation, they can form covalent adducts with proteins, and as a result, serve as key precursors for off-flavor formation during processing and storage. Most off-flavor compounds in pea protein isolates are formed via lipid oxidation. It is difficult to avoid this process because it happens at every step of protein isolation, from harvesting to storage of the final product, even from the plant’s own metabolism. The compounds that result not only taste and smell unpleasant, but they reduce the nutrient content of foods and are potentially harmful to human health. Peas naturally are low in fat, and their lipids are rich in polyunsaturated fatty acids (PUFA), such as the essential fatty acids linoleic and α -linolenic acid. PUFA can help lower cholesterol levels, but they are also particularly susceptible to degradation by lipid oxidation. The double bonds in these molecules make it easy for hydrogens to be pulled away in the presence of oxygen, leaving a radical behind. The radical degrades into unstable primary oxidation products called lipid hydroperoxides, which can either undergo reactions to produce oxygenated fatty acid derivatives called oxylipins, or break down further into volatile secondary products like aldehydes, ketones, and alcohols. Both volatile and nonvolatile lipid