Autolysis of intracellular content of Brewer's spent yeast to maximize ACE-inhibitory and antioxidant activities

Abstract

Brewer's spent yeast (BSY) is the second major by-product from brewing and is recognized as a promising source of potentially bioactive ingredients, namely the cell-wall β-glucans. However, to make the process of β-glucans’ separation from BSY profitable, new applications for the inner cell content are required. Mechanical disruption of BSY cell wall was performed to separate the β-glucans rich fraction and obtain an extract from intracellular content, rich in native proteins and enzymes, which was submitted to further autolysis. This short communication describes the optimization of BSY extract autolysis, by Response surface methodology (RSM), to produce a BSY autolysate comprising antioxidant and ACE-inhibitory activities.RSM enabled the prediction of optimum autolysis conditions. Autolysis of BSY inner cell content at 36.0 °C, 6.0 h gave a TPC of 385 μM GAE/mL, a FRAP value of 374 μM TE/mL and an IC50 value of 379 μg/mL. These experimental results were in agreement with the RSM predicted values. The combination of ACE-I and antioxidant activities in one autolysate can be very useful as functional ingredient for food industry and complement the extractive process of β-glucans from cell wall.