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International audienceNative pasture has been shown to have a strong influence on the sensory characteristics of dairy products. However, few studies have been carried out on milk flavor profiles. The aim of the present study was to evaluate the influence of cows’ pasture-based feeding on milk volatile profile. Four Sicilian dairy farms, with three different breeds and located in the Ragusano PDO cheese production area, were selected and bulk milk samples were collected during three seasons (two pasture seasons and one non-pasture season). Pasture was available in spring and autumn time but not in summer because of the climatic conditions. A total of 72 milk samples were collected. All 72 samples were analyzed by SMart Nose®; and taking into account SMart Nose results, only 48 of spring and summer milk samples were selected for gas chromatography/olfactometry (GC/O) coupled with gas chromatography/mass spectrometry (GC/MS) systems. By applying a principal component analysis on standardized means value, results by SMart Nose showed that if native pasture was present in cows’ diet, milk samples were similar in volatile fingerprint (spring and autumn time) but it strongly differed when cows’ diet lacked native pasture (summer time). However, spring milk samples showed a higher variability than milk samples collected in autumn. Using GC/O, 179 odor-active compounds were detected in milk extracts; 87% of which were chemically identified by GC/MS. Milk samples collected in spring presented 26% more compounds than non-pasture milk samples collected in summer, thus implying a pasture effect on milk aroma profile

The opportunity of replacing expensive feedstuffs with agro-industrial by-products in the diet of food producing animals is raising increasing interest while addressing global concern for the scarcity of natural resources and environmental impact of livestock farming. Hazelnut peels, rich in fiber and vitamins and characterized by a high concentration of fats, is considered a suitable ingredient to be included in the diet of ruminants. The aim of this research was to assess the effect of dietary hazelnut peels on the chemical and sensory properties of sheep cheese during refrigerated storage. To this purpose, 20 Comisana lactating ewes were randomly assigned to two experimental groups, control (C) and hazelnut peels (HP), balanced for parity, milk yield and body weight. Bulk milk collected from the 2 groups was used to produce 5 Pecorino cheeses for each group. After 40 d of aging, each cheese of each experimental group was divided into 3 pieces: 1 piece was sampled for analyses (C0, HP0) and 2 were wrapped in PVC film, simulating the condition of pre-wrapped products, and analyzed after 7 (C7, HP7) and 14 days of storage (C14, HP14) at 8°C with 80% moisture. The cheeses were analyzed for chemical and fatty acid composition, sensory analysis, odor active compounds and SmartNose. As expected, HP cheeses presented a higher lipid content compared to C, a lower content in SFA and PUFA, and a greater content in MUFA. A triangle test revealed a clear distinction between the 2 groups (α = 0.01) The sensory profile showed a significant effect on holes ( P < 0.05) and a marginal production of off-flavors linked to spicy and acid attributes for HP cheeses The volatile profile of C and HP cheese samples showed a good similarity, partially explained by the short ripening time and the absence of 2-nonanone in HP7, suggesting a higher antioxidant protection grade of this cheese compared to the others. These results were confirmed by Smart Nose analysis. Further studies on vitamin content should be conducted in order to investigate the interactions between the presence of antioxidant volatile compounds and the oxidative stability of ewe cheese.

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-Trachanas is one of the most important traditional food products of Cyprus. It is made from fermented sheep or goat's milk or a mixture of both. The fermented milk is heated and crushed wheat is added to produce a porridge mixture. The mixture is then dried and stored in the form of "biscuits". Dehydration is performed either by sun, at a domestic level, or industrially using an oven. The objective of this study was to detect differences in aroma compounds of sun-dried or oven-dried Trachanas samples. Six samples (three sun-dried batches and three oven-dried batches) were prepared to make a porridge mixture according to the Cypriot tradition. Dried Trachanas samples were chemically analysed by the electronic nose SMart Nose system, by gas chromatography-mass spectrometry (GC/MS) and by gas chromatography-mass spectrometryolfactometry (GC/MS/O). Triangle tests were also performed by a panel of 30 people from the CoRFiLaC staff in Ragusa, Italy. Principal component analysis applied to SMart Nose results showed a good separation between sun and oven-dried samples: Sun-dried samples showed a higher variability explained by the traditional process, in comparison to the oven-dried samples. GC/MS and GC/MS/O analysis showed higher numbers of compounds for the sun-dried Trachanas samples. In particular, double the number of odour active compounds were detected by GC/MS/O in the sun-dried samples, revealing that the use of the oven in the dehydration process generally resulted in a lower intensity of aroma. Triangle test confirmed instrumental results and clearly indicated detectable differences by consumers between sun-and oven-dried Trachanas.fermented food / cereal / dehydration / dairy food / aroma compound / electronic nose / gas chromatography / olfactometry