Cocoa by-product inclusion in dairy sheep diet: effect on sensory, volatile and antioxidant properties of cheese

The possibility of inclusion of agro-industrial by-products in the diet of small ruminants represents both an economical and an environmental strategy for reducing waste management by industries and the cost of feeding as well as the impact of livestock farming. Large amounts of wastes from the cocoa industry are annually produced with a considerable part represented by cocoa bean shells, considered a suitable ingredient to be included in the diet of ruminants within the limits established by European legislation. The aim of this study was to assess the effect of including cocoa bean shells in the diet of dairy sheep on the sensory, volatile, and antioxidant properties of cheese. To this purpose, 20 Comisana lactating ewes were randomly assigned to 2 experimental groups: control (CTRL) and cocoa bean shells (CBS), and received alfalfa hay ad libitum and 800g of conventional (CTRL) or experimental (CBS) concentrate containing 11.7% CBS to partially replace corn and barley of the CTRL concentrate. Bulk milk collected from each group was used to produce a total of 15 cheeses per group, obtained in 5 different days of cheese-making (3 cheeses a day per group). After 60 d of aging, each cheese of each experimental group was sampled for the analyses. The results on chemical composition revealed a greater monounsaturated fatty acids content and an increase in the nutritional indices suggesting a favorable role of cocoa bean shells dietary inclusion on the nutritive value of the cheese. The cheese sensory profile was affected by the cocoa bean shells inclusion, with more pronounced appearance, odor, aroma, and taste attributes in the product. The volatile profile showed only a few significant differences, mainly related to the cheese ripening process, and no differences were found in α-tocopherol contents in cheese fat between the 2 groups. Therefore, the coca bean shells inclusion in the diet of dairy sheep allowed to obtain a good quality cheese, without altering the characteristics associated with the typical profiles of sheep cheese. Furthermore, the use of this by-product could contribute to decrease feed costs and waste management, representing a good practice for increasing the sustainability of dairy products.

Effect of cooking temperature on alkaline phosphatase in the production of raw-milk Pecorino cheese

Alkaline phosphatase (ALP) is a native raw-milk enzyme used in many countries as the standard assay for rapidly validating the milk pasteurization process. Due to the increased restrictions on the production or import of cheeses produced from unpasteurized milk, ALP activity (<10 mU/g) in cheese was measured as a simple and reliable method to check proper milk pasteurization in cheese for both safety inspection and trading controls. In Sicily, the artisanal cheesemaking of the Protected Denomination of Origin (PDO) semi-hard cheeses made with raw sheep milk, includes the cooking of the curd, after whey separation, in a wooden vat under hot Scotta whey (≥80°C), for 3 to 4 h, and finally is left to cool at ambient temperature. Thus, the temperatures adopted during cheesemaking may inactivate the ALP enzyme. To this purpose, the aim of this study was to demonstrate how different temperatures of Scotta whey (35°C [T35], 60°C [T60], 70°C [T70], 80°C [T80], 90°C [T90], and 100°C [T100]) used during the second cooking of Pecorino cheeses after molding for 3 h, influence the ALP activity in fresh and 3-mo aged cheese, both at core and outside. The results highlight that the rate of reduction of ALP was greater with increasing temperature of the second cooking, in particular for T 80°C curd, indicating that the use of Scotta whey >80°C could be a breakpoint able to reduce the ALP activity to values <10 mU/g. Different effects between the core and the outside portions of the experimental cheeses were found, with a decrease in ALP activity more on the outside than in the core portions, in both fresh and 3-mo aged cheeses, for T80, T90, and T100 treatments. Care must be taken in using ALP to control the use of pasteurized milk in the production of PDO cheeses without considering the cheesemaking processes, such as the second cooking, which could be equal to pasteurization, and an adequate interaction of time and temperature can reduce the ALP activity to values comparable with cheeses produced with pasteurized milk.

Effect of Sicilian pasture feeding management on content of α-tocopherol and β-carotene in cow milk

This study was performed to evaluate α-tocopherol and β-carotene contents of pasture milk under ordinary Sicilian farming conditions. Fourteen dairy farms were allocated into 2 balanced groups on the basis of cultivated (CULT) or spontaneous (SPO) pasture type feeding. Bulk milk per farm was collected 4 times from February through April at 3-wk intervals. Pasture botanical and diet composition, diet nutritional quality, milk yield and composition were estimated each time. Pasture intake levels were calculated based on feed analyses, hay and concentrate amounts fed, and milk yield and chemical composition. According to pasture intake, the farms were split into low pasture intake (LPI; <29.5% of dry matter) and high pasture intake (HPI; >29.5% of dry matter) groups. Milk samples per farm were analyzed for α-tocopherol and β-carotene contents by HPLC. The SPO group had higher levels of α-tocopherol and β-carotene in milk (0.7 and 0.3 mg/L, respectively) and milk fat (19.0 and 7.5 mg/kg fat, respectively) compared with the CULT group in milk (0.5 and 0.2 mg/L, respectively) and milk fat (14.6 and 4.9 mg/kg, respectively). High pasture intake compared with LPI increased α-tocopherol in milk fat (18.0 and 16.0 mg/kg of fat, respectively). However, only in the SPO (not in CULT), HPI compared with LPI increased milk α-tocopherol (0.8 vs. 0.6 mg/L, respectively), milk β-carotene (0.3 vs. 0.2 mg/L, respectively), and milk fat β-carotene (8.4 vs. 6.6 mg/kg, respectively). Results may be related to the different botanical composition of the respective pasture types and pasture intake. Spontaneous pasture compared with CULT contained a higher mass proportion of Asteraceae, Fabaceae, Cruciferae, Euphorbiaceae, and Malvaceae plants. Milk and milk fat α-tocopherol levels were higher on test-days (TD)-1, TD-2, and TD-4 compared with TD-3. For HPI farms, milk fat β-carotene content was higher on the first 2 TD compared with the last 2 TD. These differences could be related to plant biological stage. On Sicilian dairy farms, the highest milk α-tocopherol and β-carotene contents may be obtained feeding high levels of SPO pasture in the spring.

Effect of antioxidant diets on mitochondrial gene expression in rat brain during aging

Age-related increase of reactive oxygen species (ROS) is particularly detrimental in postmitotic tissues. Calorie restriction (CR) has been shown to exert beneficial effects, consistent with reduced ROS generation by mitochondria. Many antioxidant compounds also mimic such effects. N-acetyl cysteine (NAC) provides thiol groups to glutathione and to mitochondrial respiratory chain proteins; thus, it may counteract both ROS generation and effects. In the present study we investigated, in different rat brain areas during aging (6, 12, and 28 months), the effect of 1-year treatment with CR and dietary supplementation with NAC on the expression of subunit 39 kDa and ND-1 (mitochondrial respiratory complex I), subunit IV (complex IV), subunit alpha of F0F1-ATP synthase (complex V) and of adenine nucleotide translocator, isoform 1 (ANT-1). The observed age-related changes of expression were prevented by the dietary treatments. The present study provides further evidence for the critical role of mitochondria in the aging process.