Milk and dairy products can have variable contents of antioxidant compounds that contribute to counteract the oxidation of lipids and proteins during processing and storage. The content of active antioxidant compounds is closely linked to their protection by oxidation. Freezing is one of the factors that can reduce antioxidant activity. Freezing of milk or curd is frequently used in case of the seasonality of milk production and/or seasonal increased demand for some products. In this paper, the effect of using frozen curd on the oxidative stability of buffalo Mozzarella cheese was evaluated. Samples of buffalo Mozzarella with different frozen curd content (0%, 5%, 20%, and 50%) were produced and analyzed at one and nine days. Mozzarella cheese with higher frozen curd content had a significant increase in redox potential parallel to the decrease in antioxidant activity, showing less protection from oxidation. Lipid and protein oxidation, expressed respectively by malondialdehyde and carbonyl content, increased significantly with increasing frozen curd. At nine days, carbonyls significantly increased while malondialdehyde content did not vary, showing that during storage, fat was more protected from oxidation than protein. The average carbonyl levels were comparable to those of some cooked cheeses, and the malondialdehyde levels were even lower. The results of this study stimulate the investigation of new strategies to decrease the oxidative damage in cheeses produced in the presence of factors decreasing oxidative stability.
This study investigated the effects of dietary supplementation with extruded linseed (ELS) and Padina pavonica algae extract (PP) on rabbit carcass and meat quality. Ninety-six rabbit carcasses from two production cycles were analyzed. In the first cycle (C1), rabbits were fed a control diet (1CNT), the same diet supplemented with 5% ELS (1ELS5%), and supplemented with 3.5% ELS and 0.2% PP (1LPP3.5%). In the second cycle (C2), the diets varied in composition and supplementation levels: a different control diet (2CNT), the same diet with 5% ELS (2ELS5%), and with 5% ELS and 0.2% PP (2LPP5%). Meat analyses were performed on Longissimus thoracis et lumborum (LTL) muscle for physical properties and on thigh meat (THM) for proximate composition, vitamin E, coenzyme-Q10, cholesterol, fatty acid profile, and mineral content. No significant differences in LTL physical quality were observed in C1, although LTL was brighter in C2 (p < 0.001). THM in C2 had higher fat content (p < 0.001). Dietary supplementation with ELS and PP extract significantly increased polyunsaturated fatty acids (n-3 PUFAs) and improved the n-6/n-3 ratio (p < 0.001) in rabbit meat, demonstrating their positive impact on meat quality.
Cheese is an important source of protein in the human diet, and its digestibility depends on its macro and microstructure. This study investigated the effect of milk heat pre-treatment and pasteurization level on the protein digestibility of produced cheese. An in vitro digestion method was used considering cheeses after 4 and 21 days of storage. The peptide profile and amino acids (AAs) released in digestion were analyzed to evaluate the level of protein degradation following in vitro digestion. The results showed the presence of shorter peptides in the digested cheese from pre-treated milk and 4-day ripening while this trend was not observed after 21 days of storage, showing the effect of storage period. A significantly higher content of AAs was found in digested cheese produced from milk subjected to a higher temperature of pasteurization, and there was a significant increase in total AA content in the cheese after 21 days of storage, confirming the positive effect of ripening on protein digestibility. From these results emerges the importance of the management of heat treatments on the digestion of proteins in soft cheese.
The oxidative stability of milk and dairy products is a very interesting topic for the dairy industry due to the growing demand for foods containing bioactive compounds with positive health effects. The aim was to evaluate the oxidative stability of milk intended for cheese production. The effect of storage time, heat pre-treatment, and milk pasteurization temperature on the characteristics of milk and cheese was investigated. The cheese samples were produced with pasteurized milk at both 72 and 77 °C for a time of 15 s using three types of milk: raw fresh milk processed within 48 h of milking, raw stored milk processed within 96 h, and thermized milk that was heat-treated upon arrival at the dairy and processed within 96 h of milking. In total, three repetitions were carried out for each type of milk and pasteurization. Samples of milk before and after pasteurization and cheese at 14 days of storage were analyzed. Antioxidant activity decreased from starting milk to milk after pasteurization to final cheese. The longer storage time of the milk had significant effects on the antioxidant stability of the cheese (64.95 vs. 59.05% of antioxidant activity). Thermization of the milk further reduced the stability of the cheese (54.05% of antioxidant activity). The greater antioxidant stability of fresh milk and cheeses produced with fresh milk is the first result that encourages the production of cheese from a milk that best preserves its original characteristics.
This study examines the variability of sialic acids, specifically N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), in beef from seven cattle breeds (Holstein Friesian, Red Pied, Maremmana, Chianina, Charolais, Limousin, and Piemontese). Neu5Gc, a non-human sialic acid linked to inflammation and disease risk, showed significant breed differences (p < 0.001), with the highest concentration in Holstein Friesian (61.02 µg/g) and the lowest in Piemontese (20.87 µg/g). Neu5Ac, known for its neuroprotective properties, was most abundant in Piemontese (112.99 µg/g, p = 0.032) and lowest in Limousin (81.25 µg/g). The Neu5Ac/Neu5Gc ratio, critical for dietary health, exceeded the threshold of 5:1 only in Piemontese (5.49), identifying it as a breed with a higher ratio. This study highlights the influence of breed, with limited effects of muscle type and aging, on sialic acid content. Significant correlations were observed between Neu5Gc and fatty acid classes (p < 0.05) and between Neu5Ac and polar amino acid groups (p < 0.01). The findings support selective breeding to optimize beef’s nutritional profile, enhancing its health benefits for consumers.
The search for sustainable feed ingredients has increased interest in insect-derived proteins for livestock production. This study evaluated the effects of replacing 3% soybean meal with house cricket (Acheta domesticus) meal on carcass traits, meat quality, proximate composition, and fatty acid profile of growing rabbits. Twenty-four weaned New Zealand White rabbits were assigned to either a control (CNT) or a cricket meal diet (ADM) from 35 to 85 days of age. Physical meat quality was evaluated in the Longissimus thoracis et lumborum (LTL), while proximate composition and fatty acid profile were determined in LTL and thigh muscles. Carcass performance was not affected by dietary treatment, whereas the cricket meal diet increased adiposity, resulting in greater scapular and perirenal fat deposition (p < 0.001) and a higher fat proportion in the hind leg (p = 0.011). Physical meat quality traits were unaffected, except for higher cooking loss in ADM-fed rabbits (p = 0.039). Cricket meal increased crude fat and modified the fatty acid composition by increasing n-6 PUFA (p = 0.013) and reducing n-3 PUFA (p < 0.001), resulting in a less favorable n-6/n-3 ratio. Overall, cricket meal modified lipid deposition and fatty acid composition without compromising carcass performance, although its greater lipid contribution should be considered when interpreting these effects.