Antioxidant activity of raw milk and dairy products commonly consumed in Fars province, Iran

Abstract

Dairy products play an important role in our daily diet. The objective of the present study was to assess the antioxidant capacity of raw milk and dairy products of Fars province, Iran. A total of 30 samples of raw milk and commonly consumed dairy products including high temperature short time (HTST) and ultra-high temperature (UHT) treated milk, hard cheese, doogh (drink yogurt) and yogurt were collected from a dairy plant in which raw milk bulk was supplied by farms located in Shiraz and Marvdasht regions of Fars province, Iran. The antioxidant capacity of the samples was determined using two spectrophotometric methods: 2,¬ 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and cupric reducing antioxidant capacity (CUPRAC) assays. The results were expressed as mg of dry matter. The DPPH radical-scavenging activity of raw, sterilized and pasteurized milk samples were similar and ranged from 8.46 ± 0.04 to 8.75 ± 0.08 mM EVCAA /100g dw. However, these samples exhibited significant differences (P < 0.001) among their reducing power capacities. Among the products, cheese represented the highest DPPH radical-scavenging capacity (5.02 ± 0.01 mM EVCAA /100g dw; p<0.001), while the highest reducing power activity was found in cheese samples (262.84 ± 0.18 mM EVCAA /100g dw; p<0.001). Dairy products offered a promising performance as the source of natural antioxidants.