Sustainable zero-waste processing system for soybeans and soy by-product valorization

Soybean is a rapidly growing crop plant driven by increasing demand for animal feed, plant-based protein, and human nutritional requirements. Considering the nutrient profile of soybeans, a wide range of soy-based food products are available in the market. In the United States, a significant proportion of soybeans is used for the animal feed industry, followed by human food, nutraceutical, and other industrial purposes. Soybean processing industries generate a huge number of by-products during the processing of primary soy-based products. This review article primarily focuses on creating a zero-waste food system by utilizing the soybean processing industry by-products. Soymeal (from soy-oil processing), okara (from soymilk processing), and soy whey (from tofu processing) have an excellent nutritional profile. Due to the lack of a cost-effective, sustainable food processing system, a considerable proportion of these by-products are used for animal feed purposes, industrial purposes, or deposited as waste in water bodies and soil surfaces. Key Findings and Conclusions: Valorization of soy by-products not only prevents the environment from the harmful effect of waste but could also be the key solution to address the malnutrition problem. This review brings the critical aspects of by-products utilization from soybean processing industries with an overview of cost-effective, feasible, and optimized processing technology. A zero-waste soybean processing model is proposed in this review to support a sustainable food system.