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.

Cow’s milk proteins are encoded by highly polymorphic genes characterized by several mutations which result in different allelic variants. Each allelic variant has different possible effects on cheese-making properties and on human health. β-casein A1-A3-I-B, k-casein B and β-lactoglobulin B are supposed to influence milk cheese-making properties by increasing cheese or milk yield, by varying chemical parameters, by having small casein micelle size, and by influencing rennet coagulation time (RCT) and curd-firming rate (CFR). In addition, β-casein A1-B are also considered to be a risk factor for different health diseases such as ischemic heart disease (IHD), type 1 diabetes (T1D), decreased glutathione (GSH) concentration, and milk intolerance. An LC-MS method was applied to profile, for the first time, the main milk proteins genetic variants from Aosta Valley autochtonous cattle breeds. Analyses performed on milk collected from bovines of three cattle breeds (Red Pied – VRP, Black Pied – VNP and Chestnut – CAS), either from IAR experimental farm or from herds of dairy-producers in Aosta Valley region, showed quite high frequencies of β-casein A2 and A3/I, and low frequencies of β-casein A1. Moreover, low frequencies of β-casein B in VRP breed and high frequencies of the same variant in CAS, and VNP breeds have been found. As far as k-casein is concerned allelic variant B is the most diffused in VRP while allelic variant A in VNP and CAS breeds. Finally, β-lactoglobulin most diffused allelic variant for all breeds is B. Results suggest that Aosta Valley milk has good cheese-making properties and good frequencies of β-casein A2 which may be related to beneficial effects on human health. In light of these results, it is important to develop breeding programs which take into consideration milk proteins polymorphisms to further increase the milk suitability for cheese-making process and to decrease the presence of β-casein A1 and B in drinking milk which can be a risk factor for human health.

Background: Fermented milks are a source of bioactive peptides with different potential benefits on human health (mainly antioxidant and antihypertensive effects) and may be considered as functional foods. Furthermore, those made with sheep milk have higher nutritional value and higher concentrations of proteins, fats, minerals, and vitamins, if compared to milk of other species. Objectives: Aim of this study was to perform a biochemical characterization and a comparison between sheep fermented milk (SFM) made with commercial starter cultures and sheep milk YoAlp®, a fermented milk obtained using local strains of lactic acid bacteria (LABs) (Streptococcus thermophilus and Lactobacillus delbrueckii) which have been isolated during years in Aosta Valley mountain dairy cattle farm. Methods: Sheep milk and fermented milk (Sarda and Lacaune breeds) have been collected and immediately analyzed. 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. Results: The comparison between SFM and YoAlp® peptide profile shows a higher number of peptides using autochthonous starter cultures (52) than commercial starter cultures (35). Among these peptides 20,78% and 29,87%, respectively, are supposed to be potentially bioactive (DPP - dipeptidyl peptidase-IV - inhibitor, ACE - angiotensin converting enzyme – inhibitor and antioxidant). In both products, the fatty acids profile was similar to that of origin sheep milk; concerning aromatic profile, YoAlp® shows yogurt typical aromatic assets, similar to the commercial one. As far as bioactivity is concerned, ACE inhibitor activity is high for both samples. Similar values, as expected by peptide profile analysis, have been obtained using commercial and autochthonous starters. 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 significative. Conclusions: Local strains of lactic acid bacteria from Aosta Valley seems to work as well as the commercial, preserving biodiversity and typicality. However, further analyses are needed to identify peptides generated by autochthonous LABs in order to understand microbial proteolytic activities and to investigate gastric digestion resistance of bioactive peptides which can have positive effects on human health.