Kinetics of antioxidant loss in mackerel light and dark muscle

The loss of water- and lipid-soluble antioxidants of mackerel light and dark muscle was determined as a function of time of storage on ice to provide clues as to mechanisms of oxidation and to assess the use of antioxidants to measure and predict quality. Glutathione and ascorbate decreased faster initially than alpha-tocopherol and ubiquinone in both light and dark muscle of mackerel; in dark muscle, the rate of loss of ubiquinol was comparable to the loss of the water-soluble antioxidants. Antioxidants decreased more rapidly initially in dark muscle than in light muscle. Rates of sensory quality loss in the light and dark muscles were similar except that initial lass of quality in the dark muscle was greater than that in the Light. Regression equations showed good relationships of tocopherol, ubiquinone-10, and TEARS in Light and dark muscle with storage time. Ascorbate and glutathione gave the best correlation values with sensory scores for light muscle, while a good relationship was seen in dark muscle between sensory score and reduced or oxidized CoQ, ascorbate, and glutathione. The kinetic data suggest an important role of mitochondria in lipid oxidation in mackerel dark muscle.