Valorization of Legume By-Products Based on Polyphenols and Protein Contents for Potential Nutraceutical Applications

Abstract

A significant amount of agri-food by-products is generated by large food industry production lines. Aligned with the principles of a circular economy, this project aims to recycle and valorize legumes, such as beans, green beans and soy by-products characterized by different heat treatments, maturation stages and cultivation methods. The valorization of food waste involved the development of an Ultrasound-Assisted Extraction (UAE) method to isolate polyphenols. Analytical techniques, including UHPLC-DAD-ESI-MSn, were used to identify polyphenols in legume, green bean and soy extracts obtained through UAE. Additionally, UV-Vis spectrophotometric assays measured the Total Phenolic Content (TPC) and Total Antioxidant Status (TAS), while the Kjeldahl method was employed to assess the protein content in each UAE extract. The analyses revealed a variety of valuable polyphenols in legume, green bean and soy by-products. For instance, bean by-products contain feruloyl glucaric acid derivatives, green beans by-products have different types of flavonols such as quercetin-3-O-glucuronide, and soy by-products are rich in isoflavones. These findings demonstrate the potential for formulating nutraceuticals from these by-products’ extracts.