Consumers differentiate milk-quality characteristics in relation to the production system, but data on retail milk composition are limited. This study investigated how farming methods and seasons affect proximate composition, fatty acid profile, antioxidant activity, and physicochemical characteristics of commercial cow's milk. Milk samples, both conventional (n = 84, 7 manufacturers) and organic (n = 24, 2 manufacturers), were collected monthly over a year. Farming system did not significantly affect milk composition other than fat content, whereas seasonal effects were notable, impacting the contents of ash, protein, and added water. Fatty acid composition exhibited variations influenced by both production system and season. Compared to conventionally produced milk, organically produced milk exhibited higher levels of polyunsaturated fatty acids (4.54 vs. 3.88, p < 0.01) and a lower atherogenicity index (2.23 vs. 2.50, p < 0.05). The antioxidant activity showed that conventionally produced milk exhibited better radical-scavenging activity (DPPH) (14.54 vs. 12.30 µM TE/mL, p < 0.01). Seasonal variations were evident in both free radical-scavenging activity (DPPH), with values of 12.29 µM TE/mL in winter and 15.58 µM TE/mL in spring (p < 0.05), and ferric reducing-antioxidant power (FRAP), with levels of 21.81 µM TE/mL in autumn and 27.94 µM TE/mL in spring (p < 0.05). Season significantly affected (p < 0.001) milk pH, electrical conductivity, refractive index, and freezing-point depression. In conclusion, this study showed that the farming system has a limited impact on retail milk quality compared to the significant influence of season.
Dairy products from mountain-origin milk are known for their superior composition and quality. This study aimed to examine changes in composition, nutritional quality, and antioxidant properties of milk from semi-intensively managed goats in mountainous regions during the post-weaning to end-of-lactation period. Bulk tank milk samples from 10 farms were collected bi-weekly in the period from March to September. The farms were situated in regions with an average altitude of 772.20 m above sea level. The results revealed significant variations in milk composition, with fluctuations in fat, protein, lactose, and total solids. Milk yield per doe showed seasonal differences, with the highest yield in April and the lowest in September. Fatty acid composition exhibited changes throughout the sampling period, with variations in polyunsaturated fatty acids. Nutritional indices, such as the atherogenicity index and thrombogenicity index, remained within the recommended values. Antioxidant properties, including total phenolic content, DPPH, FRAP, and ABTS, showed significant differences, with higher values toward the end of the study. Milk pH, electrical conductivity, brix value, and refractive index also exhibited variations, while density and freezing point remained relatively stable. The study provided valuable information that can be used to develop breeding and feeding plans to achieve uniform milk quality in mountainous regions.
