Hazelnut as Ingredient in Dairy Sheep Diet: Effect on Sensory and Volatile Profile of Cheese

Abstract

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.

Evaluating the Suitability of Hazelnut Skin as a Feed Ingredient in the Diet of Dairy Cows

“…The HS used in this trial showed a proximate composition very similar to that described in the available published literature [17,26]. In accordance with the results of these authors, the major component in HS was fiber (>500 g/kg DM).…”

“…The EE content was also high, falling within the ranges (109.9 to 287.8 g/kg DM) reported by Zeppa et al [17] for four different cultivars. The CP content of HS was low, being comparable to values reported by Cetinkaya and Kuleyin [25] (around 60 g/kg DM) and slightly lower than the values found by Caccamo et al [26] and Longato et al [20] (74 to 79 g/kg DM). Campione et al [27] also reported that around the 68% of protein in HS is in the form of unavailable nitrogen (acid detergent insoluble protein).…”

“…In that trial, the concentrate containing HS had 5.6 times higher EE than the control concentrate. When analyzing Pecorino cheese derived from the same ovine milk, Caccamo et al [26] reported a significantly higher lipid content in the cheese manufactured using the HS-derived milk. In our trial, the inclusion level of HS in the cow diet was about half of that used by Campione et al [27] (6.0% vs. 11.3%) and increased the EE content of the whole diet by 37%.…”

“…Only two very recent studies are currently available on the inclusion of HS in the diets of ruminants and on the related effects on animal product quality. Caccamo et al [26] evaluated how the inclusion of HS in the diets of dairy ewes can affect the chemical and sensory characteristics of ovine cheeses, showing the by-product to have significant impacts on the lipid content and FA and sensory profiles of the cheeses. The replacement of dried beet pulp by HS in a commercial formulation for lactating ewes had no effects on feed intake and milk yield [27].…”

Effect of Feeding Hazelnut Skin on Animal Performance, Milk Quality, and Rumen Fatty Acids in Lactating Ewes

“…To our knowledge, no study has evaluated the suitability of this by-product as feedstuffs for ruminants. Only our recent paper investigated the sensory and volatile profile of cheese produced with milk from sheep fed HS [12], but the effect on milk yield and quality was not investigated.…”