Major Antioxidants and Methods for Studying Their Total Activity in Milk: A Review

The presence of antioxidants in food contributes to the preservation of its taste and technological qualities, preventing its spoilage for a longer time, which is important at all stages of production and storage. The major antioxidants are vitamins, proteins (primarily, enzymes), peptides, amino acids, fatty acid residues of lipids, etc. There is currently an explosive growth in the development of methods for assessing the content and effectiveness of particular antioxidants but not the total antioxidant activity (AOA) in raw milk and food systems. This article provides a critical overview of the most important AOA methods, their mechanisms and applicability, advantages, and limitations (primarily, for antioxidants of milk and dairy products). Among all the antioxidant indicators of milk, the simplest and sufficiently informative is the detection of the total amount of water-soluble antioxidant (TAWSA), which is confirmed by comparison of numerous publications and practical results of various methods (as summarized in this review). It is important to emphasize that the TAWSA of milk is an "integral characteristic" of the most valuable biosubstances (possessing AOA) together. Therefore, the TAWSA method is recommended for assessing AOA in raw milk as an "integrated indicator" in dairy husbandry.