Effectiveness of modified atmosphere and vacuum packaging in preserving the volatilome of Stelvio PDO cheese over time.

We aimed to assay the effectiveness of vacuum or modified atmosphere packaging in preserving the organoleptic characteristics of already ripened slices of Stelvio Protected Designation of Origin cheese during 3 months of storage. A multi-omics panel, including metagenomic and metabolomic analyses, was implemented together with physicochemical and sensory analyses. Among the 177 volatiles identified, 30 out of the 50 potent odorants were found to be prevalent, regardless of packaging. Isovaleric acid showed the highest relative intensity in all samples. Caproic and caprylic acids always increased during storage, while metabolites such as dodecane and 2,3-butanediol always decreased. Slow proteolysis occurred during storage, but did not differentiate cheese samples. The type of packaging differentiated the microbiota and volatile profile, with modified atmosphere packaging keeping the volatilome more stable. Out of the 50 potent odorants, 9 were relevant to sample discrimination, with 8-nonen-2-one, 2-nonanone, and caproic acid being more abundant in stored samples.

How starter cultures affect the peptidomic profile and bioactive activities of the Asiago-PDO cheese throughout ripening.

Our study investigated the chemical, microbiological, and bioactive peptide profiles of Asiago Protected Designation of Origin (PDO) cheese from two dairies (Dairy I and II) produced over two consecutive days (batches) and analysed during three months of ripening. The effect of different starter cultures was evaluated. The microbiome varied between the dairies and batches, with curds post-salting dominated by the starter culture-associated genera. During ripening, there was an increasing trend in the Lactobacillus genus, especially for Dairy I, which used an industrial starter. Bioactive peptide intensities differed throughout ripening due to the extent of proteolysis, and their intensity or concentration evolved, modifying, and differentiating profiles. The industrial starter used in Dairy I had the highest relative intensity (average value 76.50%) of bioactive peptides after three months of ripening. In contrast, the cheeses made with natural milk starter (Dairy II) had lower total relative intensity (average value 47.75%) but produced ACE-inhibitory peptides through sub-dominant strains and non-starter lactic acid bacteria. The importance of autochthonous strains of each micro-region even within a delimited PDO production area was highlighted.

High protein yogurt with addition of Lactobacillus helveticus: Peptide profile and angiotensin-converting enzyme ACE-inhibitory activity.

In order to evaluate differences in the peptide profile and bioactive potential in dairy products, by increasing the protein content and using proteolytic bacteria strain to enable the release of bioactive peptides, a high-protein yogurt with adjunct culture was developed. The effect of protein content, the addition of Lactobacillus helveticus LH-B02, and storage time were evaluated. The qualitative analysis of peptide profile was performed using a mass spectrometry approach (MALDI-ToF-MS), and the potential bioactivity evaluated by ACE inhibition activity. Protein content did not affect the peptide profile in yogurts, and the addition of Lactobacillus helveticus LH-B02 favored the formation of peptides recognized as bioactive, such as αS1-CN f(24-32) and ß-CN f(193-209). Increased protein content and adjunct culture addition increased the ACE inhibitory activity. The combination of both factors had no additional effect on the bioactive potential of yogurts.