Optimization of Hydrolysis and Identification of Bioactive Peptides in Brewery Yeast Residuals

Abstract

Industrial waste products are of biotechnological interest due to their abundance and can be utilized as protein sources for the production of bioactive peptides through hydrolysis. The utilization of yeast residues from the brewing industry has been demonstrated to be a viable method for obtaining protein hydrolysates. The degree of hydrolysis and soluble total protein of the hydrolysates were evaluated for optimization purposes to achieve a product with a high proportion of soluble organic nitrogen, increased levels of bioactive peptides and amino acids. Both alkaline and enzymatic hydrolysis processes were tested. The hydrolyses were carried out with the aim of large-scale implementation. The treatments were effective in liberating intracellular content and producing biologically functional hydrolysates, with degree of hydrolysis values ranging from 28 to 63% and total protein from 2.95 to 8.28% at the optimum points confirmed by statistical analysis (analysis of variance (ANOVA)). The hydrolysate produced with Alcalase® exhibited the highest peptide intensity, while the hydrolysate produced with Flavourzyme® showed the highest concentration of free amino acids. The peptides were identified by mass spectrometry and were found to have biological activities according to the Biopep database. This study presents a quick and economically feasible approach for the implementation of a pilot project for the reuse of this waste.