Processing opportunities and challenges for plant-based proteins

With demand for nutritious and functional protein-rich ingredients rising, there are opportunities to acquire protein from new/ emerging sources, as well as from coproducts of agro-food industry. Some of these sources include plants/ seeds and oilseeds, microalgae, fungi, cell/ microbial, and insect protein; however, each of these may have their own unique challenges in terms of extraction, nutritional profile, bioactivity, techno-functional properties, safety, allergenicity as well as in food and feed applications. Some of the challenges for plant/seed proteins are that they have relatively lower extraction yields and relatively inferior functional/ nutritional aspects, including off-flavor and digestibility. Protein quality in defatted meals is also impacted by harsh oil removal process, which is further exacerbated by the downstream protein extraction and isolation conditions (pH, ionic strength, temperature etc.) resulting in protein denaturation, aggregation, and potential loss of functionality. Also, plant proteins have other issues such as off-flavors, astringency/ taste, allergenicity, and antinutritional factors that reduce mineral bioavailability and protein absorption. Various food processing techniques can be used to reduce/ remove these aspects of protein ingredients; fermentation, germination, heating, enzymatic, or acidic treatment, membrane separation etc. have been employed to improve protein purity and quality. The choice of processing technology, even for oil removal from oilseed, impacts protein extraction and quality. For example, protein recovered from meal/ fibers of aqueous oil extraction were of better quality than from desolventized meals. Emerging physical and biochemical processes, such as high-power sonication, extrusion, high-pressure processing, microwave, pulsed electric field, enzymatic pretreatment (pectinase, proteinase, carbohydrase), and fermentation are reported to increase protein extraction efficiency, removing/ reducing allergenicity, and modify functional characteristics. This presentation will discuss such processing challenges and opportunities for plant-based proteins for extraction and downstream isolation, as well as their impact on important functional characteristics.