Chemical Characteristics and Oxidative Stability of Buffalo Mozzarella Cheese Produced with Fresh and Frozen Curd

Abstract

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.

Effect of Storage and Heat Treatment of Milk Destined for Cheese Production on Its Oxidative Characteristics

“…In fact, the MDA content is often used as a marker of oxidative damage in cheese, varied from 0.22 to 0.25 nmol g −1 and are not significantly different (p = 0.4957) in the three groups. These values were lower than average values found in buffalo Mozzarella cheese (0.36 nmol g −1 ) [23] and in buffalo Ricotta cheese (1.51 nmol g −1 ) [50]. The MDA content of our cheese samples was also lower than the data for other dairy products [51] and well below the threshold indicated by some authors for other foods [52].…”

“…The FAST method (Fluorescence of Advanced Maillard products and Soluble Tryptophan) was used to evaluate the modifications induced in milk by heat-treatments analyzing tryptophane and advanced Maillard's products in samples [25,26]. This method has also been applied to Mozzarella cheese in a previous work [23].…”

“…The antioxidant activity of the samples was analyzed by 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) method, as reported by Unal [27] and Rinaldi et al [23]. The DPPH radical is reduced by the antioxidant compounds of the sample and the antioxidant activity expresses the capacity of the sample to inhibit the DPPH radical.…”

“…To value oxidation level in cheese after storage for 14 days, tryptophane, advanced Maillard's products and antioxidant activity were determined such as for milk using the same methods reported below. Moreover, Malondialdehyde (MDA) analysis was carried out as reported by Rinaldi et al [23] to test fat oxidation in cheese samples. The analyses were carried out on clopped samples frozen at −80 • C. For each analysis, at least two repetitions of each sample were performed.…”

Impact of Freezing on the Microbiological Quality and Physical Characteristics of Buffalo Mozzarella Cheese

“…About whiteness, its increase toward yellow color during the freezing storage is probable due to the modifications of the milk characteristics; while the increased hardness of the BMC was probably due to casein hydrolysis. The increased oxidation state associated with the development of off-odors, instead, was associated with the oxidation of the lipid phase [ 30 ] and also from non-enzymatic browning [ 20 ].…”