Degree of antioxidant protection: a parameter to trace the origin and quality of goat's milk and cheese.

Traceability is an essential tool in reassuring consumers and traders that food is as safe, authentic, and of good quality as expected. Today, food traceability procedures often consist of attached documents and declarations, but scientific parameters that could objectively identify a product would be preferable. Scientific efforts in this area are mostly focused on selection and validation of experimental indicators that would be useful for tracing a food product in any step of its commercial life, describing its raw materials, processing procedures, and storage conditions. In this research, milk and cheese samples from zero grazing and grazing goats were studied to identify a tracing parameter correlated to the feeding system. In particular, alpha-tocopherol and cholesterol were analyzed by HPLC on a normal phase column and were combined to calculate the degree of antioxidant protection (DAP). This parameter, expressed as the molar ratio between antioxidant compounds and an oxidation target, is useful for tracing and distinguishing products from grazing and zero-grazing animals. Degree of antioxidant protection values greater than 7.0 x 10(-3) were found in samples from grazing goats and values lower than 7.0 x 10(-3) were found in samples from zero-grazing goats, for both milk and cheese, meaning that cholesterol was highly protected against oxidative reactions when herbage was the only feed or was dominant in the goat diet. The reliability of DAP to measure the antioxidant protection of cholesterol appeared more effective when the feeding system was based on grazing than when cut herbage was utilized indoors by animals. The DAP index was able to distinguish dairy products when the grazed herbage in the goats' diet exceeded 15%.