Evaluation of in vitro bioactive properties of protein hydrolysates of brewers’ spent grain (BSG) obtained through solid-state fermentation using A. oryzae and functional characterization of BSG

Abstract

Bioactive peptides are novel, highly selective, and effective signaling molecules that are used for different purposes depending on their activity, which can be, antioxidant, anti-inflammatory, antihypertensive, anti-aging, among others. Peptides can be found in various sources such as animal products, plant-based foods and agro- industrial waste generated in processes. Mexico is the 4th largest beer producer in the world and generates about 2.4 billion kilograms of spent grain malt (BSG) per year. In this study, brewers spent grain without hops (BSG-0) and brewers spent grain with hops (BSG-H). These agro-industrial residues contain 23.81% and 20.59 % of proteins dry weight, which makes it a potential source for the production of functional peptides. Both matrices were used to develop solid state fermentation with Aspergillus oryzae for 5 days but best results according to protein concentration and DPPH radical scavenging activity were achieved after 4 days and for the non- fermented control for the BSG-H. After that a process of protein fractionation was carried out with a >3 kDa filters. Cosmeceutical effect as well as antihypertensive, antidiabetic and antioxidant activity were evaluated for each complete raw material and their respective fractions.