Biochemical characterization of YoAlp®: a sheep-fermented milk obtained with autochthonous starter cultures

Abstract

Fermented milks are a source of bioactive peptides with different potential benefits on human health and may be considered as functional foods. Sheep milk and fermented milk have been collected and a biochemical characterization, by a proteomic approach, GC/MS and microtiter plate assay methods, have been conducted to evaluate their peptide, fatty acid and aromatic profile, and to assess potential health promoting effects. Furthermore, a comparison between sheep-fermented milk (SFM) made with commercial starter cultures and YoAlp®, a sheep-fermented milk obtained using local strains of lactic acid bacteria, has been performed. Peptide’s profile comparison shows a higher number of amino acidic frequencies using autochthonous starter cultures than commercial ones. Among these peptides, 20.78% and 29.87%, respectively, are supposed to be potentially bioactive. Furthermore, in both products, the fatty acid profile was similar to that of origin sheep milk, and concerning aromatic profile, YoAlp® shows yogurt typical aromatic assets. Considering bioactivity, ACE inhibitor activity is high for both samples. Similar values, as expected by peptide profile analysis, have been obtained. Even in the case of antioxidant capacity, peptide profile bioactivity prediction has been confirmed by the assay showing a DPPH inhibition higher for SFM than for YoAlp®, but this difference is not statistically significant. Local strains of lactic acid bacteria seem to work as well as the commercial, preserving biodiversity and typicality. However, further analyses are needed to understand microbial proteolytic activities and to investigate gastric digestion resistance of bioactive peptides.