Fermented soy products: A review of bioactives for health from fermentation to functionality

The increasing prevalence of metabolic diseases and the global drive toward achieving Sustainable Development Goals (SDGs) underscore the need for sustainable, nutrient-dense foods. Soybeans (Glycine max), a critical global crop, offer promising solutions; however, their predominant use as animal feed raises concerns regarding food security and environmental sustainability. Fermented soy products—including tempeh, natto, and miso—are rich in bioactive compounds such as peptides and isoflavones, which offer potential therapeutic effects and hold cultural and nutritional significance. These fermented products provide bioactive profiles with unique health-promoting properties. This review critically examines the bioactive compounds generated through fermentation, focusing on their bioconversion pathways in the gastrointestinal tract and their metabolic implications for human health. Recent consumer demand for novel food ingredients with additional biological benefits has fueled research into advanced extraction techniques, enhancing the functional applications of bioactive compounds from these soy-based products. This review further explores innovations in extraction methods that improve bioactive yield and sustainability, reinforcing the applicability of these compounds in health-promoting food interventions. The originality of this review lies in its in-depth exploration of the gastrointestinal bioconversion of fermented soy bioactive compounds alongside the late sustainable extraction methods designed to optimize their use. Future research should aim to refine fermentation and extraction processes, investgate synergistic microbial interactions, and develop environmentally sustainable production methods. These efforts have the potential to position fermented soy products as essential contributors to global nutritional security and sustainable food systems, addressing both public health and environmental needs.