Valorization of spent brewer's yeast: Optimization of hydrolysis process towards the generation of stable ACE-inhibitory peptides

Abstract

Establishing of a bio-based and green society makes it possible to take actions to exploit high value resources that can be converted into valuable biological ingredients. Brewer's spent yeast is a natural byproduct from the brewing industry with high biological and nutritional richness. In the present research, the effect of autolysis and subsequent hydrolysis of spent brewer's yeast, using an extract of Cynara cardunculus was investigated by response surface methodology, to define the optimal conditions with maximized angiotensin converting enzyme inhibitory activity (ACE-I). The models describe maximum autolysis obtained at 70 °C for 5 h followed by hydrolysis at 4% (v/v) E/S ratio for 4.5 h, where the peptide extract obtained had IC50 of 146 μg mL−1 of protein content. Nanofiltration allowed to produce a fraction with <3 kDa exhibiting highest inhibitory activity (IC50 84.2 μg mL-1) and showed to be stable in vitro gastrointestinal system maintaining its activity. The results suggest an alternative use of brewer's byproduct as source of beneficial ingredient in the prevention and/or treatment of hypertension, where the protein hydrolysis improves ACE-I activity.