Utilization of Tofu By-products as an Alternative Source of Bioactive Peptide Lunasin

Utilization of tofu by-products as an alternative source of bioactive peptide Lunasin Lunasin is a 5kDa water-soluble bioactive peptide present in soybeans with anti-inflammatory, anti-carcinogenic, and chemotherapeutic properties. Current mechanisms for obtaining Lunasin from soybeans involve complicated and expensive methods that limit its utilization to a laboratory scale. Tofu is a cheese-like product obtained from soybeans. Whey and okara are the major by-products of the process and are mainly destined for animal feeding or as ingredients for food preparations, but their potential application as a sources of lunasin remains unexplored. Therefore, the aim of this study was to stablish if tofu by-products are suitable sources for obtaining lunasin enriched material by applying simple and easily scalable methods. Tofu was prepared from soybeans by a standardized procedure, and calcium was used to induce preferential precipitation of lunasin present in the by-products. Precipitate and supernatant fractions were characterized by measuring protein content, protein profile, lunasin content, and presence of isoflavones via Bradford assay, electrophoresis, western blot and HPLC respectively. Liquid fractions showed a wide distribution of proteins while calcium precipitates only contained low molecular weight proteins (<15kDa). Both fractions contain negligible amounts of isoflavones and a significant concentration of lunasin, indicating that tofu by-products can be used as a source of lunasin enriched material.