-The aim of this study was to verify the variation in fatty acid composition of milk, and derived cheese, when dairy cows were grazed on different alpine vegetation types. An experimental design was developed to highlight the effect of pasture composition on milk and cheese fatty acid profiles, thereby mitigating the other variables (altitude, animal physiology, and animal management). Two dairy cow groups were grazed on two different key alpine vegetation types (Type 1: Trifolium alpinum, Nardus stricta, and Carex sempervirens and Type 2: Festuca nigrescens, Alchemilla xanthochlora, and Phleum alpinum). Bulk milk was collected separately from each group for 6 days, from which 12 artisanal cheeses were produced and ripened for 60 days. The fatty acid (FA) composition of the bulk milks and cheeses varied with the type of vegetation. Milk and cheese derived from cows that were grazed on Trifolium alpinum-dominated pastures were richer in long-chain FAs, unsaturated and monounsaturated FAs (particularly oleic acid), and odd-chain saturated FAs (such as C15:0 pentadecanoic and C17:0 heptadecanoic acids) while those from Festuca nigrescens pastures contained more short-and medium-chain FAs, saturated FAs, and α-linolenic acid. Furthermore, our results showed that in alpine grazing systems, milk and cheese FA profiles changed when cows were grazed on pastures with a different botanical composition, probably due to differences in forage quality and concentration of bioactive secondary metabolites. These results have to be taken into account for the valorization of the nutritional characteristics and for the traceability of grass-fed dairy products.fatty acid / milk / cheese / grassland biodiversity / alpine pasture / grazing acide gras / lait / fromage / biodiversité des pâtures / pâture alpine / pâturage

Oxysterols are products of enzymatic and/or chemical cholesterol oxidation. Their measurement during and after a milk production chain could represent a useful tool to monitor and increase the commercial and nutritional value of milk.

The composition of the volatile fraction of Polygonum bistorta L. (also known as bistort or snakeroot) was investigated. Fresh aerial parts of this plant species were collected in the Western Italian Alps during the summer at three different phenological stages, namely vegetative, flowering, and fruiting, and steam-distilled in a Clevenger-type apparatus. The oils accounted for 0.004 to 0.010% of the fresh plant material, and their compositions were determined by GC/FID and GC/MS. The composition of the oils during the vegetative period varied both in quantity and quality; several classes of compounds were found with a predominance of alcohols in the vegetative phase, terpenes and linear-chained saturated hydrocarbons in the flowering phase, while saturated aliphatic acids and their methyl esters were predominant in fruiting phase. The most abundant compounds were 3-methylbut-3-en-1-ol in the vegetative phase, linalool in the flowering phase, and dodecanoic acid and its methyl ester in the fruiting phase. The obtained essential oils were then tested against two major bee pathogens, i.e., Paenibacillus larvae and Melissococcus plutonius, and against a reference bacterial species, Bacillus subtilis. Data were compared to those obtained with reference standards used against those pathogens such as the essential oils obtained from leaves and bark of Cinnamomum zeylanicum (cinnamon), and the antibiotic oxytetracyclin.

In this study, proton transfer reaction-mass spectrometry (PTR-MS), coupled with a time-of-flight mass analyzer and a multipurpose automatic sampler, was evaluated as a rapid and nondestructive tool for the quality control of anhydrous milk fat. Anhydrous milk fats packed in cardboard and bag-in-box were compared during refrigerated shelf life at 4°C for 9 months. Anhydrous milk fat samples were taken at 120, 180, and 240 days and measured by PTR-MS during storage at 50°C for 11 days. Univariate and multivariate data analysis were performed in order to classify samples according to the packaging type and compare aromatic profiles. Markers related to both packaging and storage duration were identified, and all stored samples were clearly distinguishable from reference fresh samples. Significant differences in some key butter aroma compounds such as 2-pentanone, 2-heptanone, 2/3-methylbutanal, acetoin, and butanoic acid were observed between different types of packaging. During the refrigerated storage, differences related to packaging are more evident, while during the storage at 50°C, the fat oxidation induced by the high temperature becomes the most relevant phenomenon independently of the packaging type. These results indicate the importance of avoiding anhydrous milk fat storage at 50°C for long times during industrial production processes. All together data demonstrated the viability of PTR-MS as a rapid and high-sensitivity tool in agroindustry quality control program.