Peptide-rich extracts from spent yeast waste streams as a source of bioactive compounds for the nutraceutical market

Spent yeast is one of the main fermentation process by-products and several bioactive ingredients have been extracted from it, such as mannans and β-glucans. These extraction processes generate waste streams rich in protein, that can still be used to produce peptide-rich extracts. This work describes the use of a scalable and low-cost process to obtain yeast peptide extracts in a circular economy concept. Peptide fractions produced contained 48.3 to 86.4% of protein (w/w) and essential amino acids amounts higher than those defined by FAO and WHO references. Regarding their bioactive properties, extracts exhibited strong antihypertensive and antioxidant activities. Furthermore, an inhibition of 62.0–71.3% in HMG-CoA reductase was observed, a feature hereby described for the first time, thus stating the cholesterol-lowering capacity of yeast peptides. In conclusion, due to their combined nutritional and bioactive characteristics, the produced yeast peptide extracts are good candidates for dietary supplementation and functional foods.