Colostrum-derived bioactive peptides obtained by fermentation with kefir grains enriched with selected yeasts

The aim of this study was to improve the bovine colostrum biological function through fermentation with kefir grains enhanced with selected yeasts, for developing new nutraceutical and cosmeceutical products. It was found that fermentations with coculture of 2.5 g% artisanal kefir grains and selected yeast strains (106 CFU/100 mL) increased the functional quality of the fermented products compared to the product obtained only with kefir grains. Fresh fermented products obtained with a consortium based on kefir grains and Candida lipolytica MIUG D67 demonstrated an increased antioxidant activity of 2.69 mM Trolox Equivalent/g, after 48 h of fermentation. Instead, peptide fractions with MW<10 kDa isolated by membrane filtration from lyophilized fermented products, based on colostrum fermentation with kefir grains enhanced with Candida lipolytica MIUG D99 starter, presented markedly increase in vitro of ABTS radical scavenging activity, similar to a concentration of 2 nM captopril. These results indicated their possible application in enhance of the quality of the fermented products in order to increase the postbiotic composition with functional impact in vivo.