Unraveling the impact of tempeh fermentation on protein nutrients: An in vitro proteomics and peptidomics approach.

Understanding how fermentation enhances the nutritional characteristics of legumes is essential for maximizing their potential as sustainable protein sources. This study investigates proteomics differences between soybeans and tempeh, a fermented soy product, aiming to elucidate the mechanisms that contribute to the differences in protein nutrients. Deep proteomics analysis of commercial soybean and tempeh suggests that Rhizopus fermentation promotes proteolysis, particularly targeting Asn and Phe, and thus increased neopeptide generation in tempeh samples. Data supports that the absence of proteinase and protease inhibitors during fermentation promotes the global proteolysis effects. In vitro gastrointestinal digestion of tempeh demonstrated enhanced digestibility, characterized by shorter peptide chains in the digesta. Peptidomics profiling identified digest-resistant domains and peptidyl motifs, offering insights for further digestion enhancement. These findings highlight tempeh's superiority as a plant-based protein source, emphasizing its nutritional advantages through reduced antinutritional factors and improved protein bioavailability, thereby supporting its role in a healthy diet.