Antioxidant potential of protein hydrolysates from poultry by-products obtained by microbial fermentation.

Protein hydrolysates and bioactive peptides are promising components with antioxidant properties. This study aimed to evaluate the antioxidant activity of protein hydrolysates obtained from microbial fermentation of broiler chicken gizzards using a concentration of bifidobacteria and propionic acid bacteria incorporated into whey. The total antioxidant capacity was determined by the FRAP method, the antiradical activity was determined using the DPPH assay with the detection of the IC 50 index to assess the antioxidant potential. The results showed that the FRAP antioxidant activity of the experimental hydrolysate sample obtained by fermentation using bifidobacteria was 30 % lower than that of other samples. However, this sample exhibited the greatest free radical scavenging effect, with an IC 50 of 1.363 mg/g. The content of free amino acids and peptides was also determined by UHPLC combined with mass spectrometry. The properties of peptides were identified by the in silico method using the BioPep and PeptideRanker databases. The research results showed an increase in the content of free amino acids in hydrolysates during microbial fermentation. The content of a bioactive peptide with antioxidant properties — VW, as well as several peptides with potentially high antioxidant properties, was revealed. The results obtained show the prospects for obtaining protein hydrolysates from poultry by-products by their microbial fermentation, as well as the need for further deeper studies of peptides with potential antioxidant properties.