Comparison of antioxidant properties of persimmon vinegar and some other commercial vinegars in radical-scavenging assays and on lipid oxidation in tuna homogenates

Five kinds of vinegars (two kinds of persimmon vinegars, unpolished rice vinegar, polished rice vinegar, and apple vinegar) were evaluated for their scavenging activity towards 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, superoxide radicals, and hydroxyl radicals, and for their antioxidant activity in tuna homogenate. The total phenolic content was also determined by the modified Folin-Ciocalteu method. Markedly high phenolic contents and radical-scavenging activities were found for vinegar made from persimmon Saijyo varieties, and unpolished rice vinegar. When incorporated into fatty tuna homogenates, persimmon vinegar effectively inhibited lipid oxidation in the homogenates. Persimmon vinegar may be as useful in fish processing as are other naturally occurring antioxidants, helping to prevent the formation of off-flavour in fish and their products and to increase shelf life.