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.

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.

Sialic acids (SIAs) are bioactive compounds present in glycoproteins and glycolipids, playing key roles in human physiology. N-acetylneuraminic acid (Neu5Ac), the only sialic acid synthesized by humans, contributes to neurodevelopment and immune function, whereas N-glycolylneuraminic acid (Neu5Gc), acquired from animal-derived foods, is potentially harmful, showing pro-inflammatory properties. Accordingly, a high Neu5Ac/Neu5Gc ratio represents an important nutritional indicator. This study quantified the two main forms of SIA in five commercial cheese types (mozzarella, stracchino, caciotta, robiola, ricotta) produced from cow (C), buffalo (B), and goat (G) milk, as well as in laboratory cheesemaking from 1000 g of milk from each species. Neu5Gc concentrations were significantly higher in G cheeses (p < 0.001), while Neu5Ac was more abundant in C cheeses (p < 0.05). Consequently, the Neu5Ac/Neu5Gc ratio was markedly higher in C and B cheeses (24.11 and 21.57, respectively) than in G (1.29), reflecting species-specific glycosylation patterns. Among cheese types, ricotta produced from whey exhibited the highest SIA concentrations among all species, followed by robiola, mozzarella and stracchino. In contrast, caciotta showed the lowest SIA levels. The laboratory cheesemaking trial confirmed that most SIAs remained bound to whey proteins. These findings highlighted the combined effect of milk species and cheesemaking on sialylation, with potential nutritional implications.