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Despite native whey (hereafter termed WHEY) being a watery by-product rich in high-value nutritional components, it poses environmental concerns. Recently, the techniques of thermal-mechanical microparticulation to produce microparticulated whey (MPW) and a further process to ferment MPW (FMPW) were suggested, in order to recycle whey into a protein concentrated soft dairy cream that acquires also fat mimicking functionality. Aiming at monitoring the effects of this recycling process on the products’ metabolic profiles, samples (n = 8) of WHEY, MPW and two sub-types of FMPW were analysed by combining direct analysis in real time coupled with high resolution mass spectrometry (DART-HRMS). The most informative ions were used to build a partial least squared discriminant analysis (PLS-DA) model to assess the biochemical compounds that characterize and differentiate WHEY from MPW and FMPW. The DART-HRMS fingerprints acquired in negative mode accurately differentiated samples throughout the steps of microparticulation and fermentation. Post-fermentation, greater relative abundances of lactic acid, glucosamine and histidyl-aspartic acid were detected in both subtypes of FMPW, which were moderately differentiated by DART-HRMS. Moreover, while WHEY and MPW contained high relative abundances of hydroxyglutaric and malic acids, the fermented derivates (FMPW) were characterised by elevated levels of volatile compounds (tetradecanal, hexadecene and tetradecene) and fermentative end-products (diethyltartrate and histidyl-aspartic acid). DART-HRMS successfully captured a pool of informative biomarkers useful to understand the chemical and metabolomic changes occurring in microparticulation and fermentation processes used to recycle whey. This analytical technique is an operative supporting step needed for comprehensive assessment of the nutritional and organoleptic properties of the proposed whey-based soft cream dairy food.

The effectiveness of dry ageing with regard to retaining meat quality is still subject to debate. At 4 d post mortem, samples of boneless strip loins were excised from young Charolais carcasses and then stored for a further 26 d in a cooler, either vacuum-packaged (VP) or dried-aged (DA). Loin samples were also dissected 7 d post mortem as a control treatment (CT). Chemical, instrumental and microbiological data (n = 18) were determined in longissimus dorsi and underwent ANOVA to estimate the differences in the ageing fixed factor split into two orthogonal contrasts: control vs. aged and VP vs. DA. Ageing loss (both surface dehydration and water purge) was greater in DA compared to VP samples, resulting in the lowest moisture content and highest crude protein and fat percentage in DA loins. The ageing method did not affect meat surface colour, except for redness, which had the lowest value in DA samples. Meat tenderness improved a similar amount following both VP and DA ageing treatments. Compared to the control, prolonged ageing raised both the peroxide value and the total microbial count, especially in DA samples, though both remained within the recommended limits. In summation, both ageing methods improved beef meat tenderisation, preserving its shelf life.

The study aimed to assess the seasonal variation in raw milk volatile organic compounds (VOCs) from three indoor feeding systems based on maize silage (n = 31), silages/hay (n = 19) or hay (n = 16). After headspace solid-phase microextraction (HS-SPME), VOC profiles were determined by gas chromatography (GC). Chemical and VOC (log10 transformations of the peak areas) data were submitted to a two-way ANOVA to assess the feeding system (FS) and season (S) effects; an interactive principal component analysis (iPCA) was also performed. The interaction FS × S was never significant. The FS showed the highest (p < 0.05) protein and casein content for hay-milk samples, while it did not affect any VOCs. Winter milk had higher (p < 0.05) proportions of protein, casein, fat and some carboxylic acids, while summer milk was higher (p < 0.05) in urea and 2-pentanol and methyl aldehydes. The iPCA confirmed a seasonal spatial separation. Carboxylic acids might generate from incomplete esterification in the mammary gland and/or milk lipolytic activity, while aldehydes seemed to be correlated with endogenous lipid or amino acid oxidation and/or feed transfer. The outcomes suggested that VOCs could be an operative support to trace raw milk for further mild processing.