Animal foods have long been the primary source of essential amino acids and dietary protein, the second most important macronutrient in human nutrition. However, traditional animal food production is unsustainable, requiring significant land use, contributing to greenhouse gas emissions, and raising ethical concerns. Furthermore, regular consumption of a diet dominated by animal meat has been linked to the development of several chronic diseases. Plant-based proteins offer a promising solution, not only because legumes have a long history of cultivation and use, are readily available in many parts of the world, and are inexpensive to produce, but also, most importantly, because plant-based protein production is environmentally friendly and sustainable.
Currently, soy protein and wheat gluten are the two most widely used plant-based protein ingredients as alternatives to animal protein. However, due to gluten sensitivity and the allergenic potential of soy protein, many consumers cannot consume products containing these ingredients. Therefore, new plant-based protein sources are needed. Among potential plant-based protein sources, such as nuts, grains, legumes, vegetables, and fruits, legumes are particularly suitable due to their high protein content and nutritional properties.
In recent years, various legume proteins from sources such as beans, lentils, chickpeas, and peas have been explored as alternatives to soy protein, with some commercial success, such as pea protein. As a new type of legume protein, pea protein has gained popularity in the global food industry due to its low cost, availability, high nutritional value and health benefits.
Soy protein extraction methods
The two traditional methods for protein extraction are wet extraction and dry extraction. Compared to wet extraction, dry extraction yields lower protein purity. However, dry extraction conserves resources and costs while preserving the protein’s original structure and function. Wet extraction is costly, time-consuming, and labor-intensive, and produces large amounts of wastewater and chemicals, negatively impacting the environment. Research has developed a combined wet-dry extraction method, whereby the protein-rich soy flour fraction obtained through dry extraction is further subjected to wet extraction to improve purity. However, this method is not currently widely used.
Due to its accessibility, sustainability, nutritional value, and wide applicability in a wide range of food products, soy protein holds great promise as a food alternative to traditional animal protein. Currently, pea protein is the most commercially available and widely used of all soy proteins. However, more research is needed to identify proteins from legumes (other than pea) that possess sufficient functional properties to guarantee food safety. Future breeding efforts could target these proteins by selecting varieties with higher protein and limiting amino acid content. Plant breeding could also be used to select varieties with lower levels of off-flavor compounds. Regulatory and standardization organizations need to develop standards or guidelines for protein extraction, protein functional testing, and the identification of protein concentrates and isolates. Future research should also incorporate innovative technologies such as 3D printing, artificial intelligence and big data systems, precision fermentation, and extrusion to develop novel applications for soy protein ingredients, such as personalized and precision nutrition, bioactive peptide production, flavor development, and edible protein films. Finally, consumers need to be more aware of the potential health benefits of soy ingredients and their role in sustainable agriculture and food production.