Studies on rancidity inhibition in frozen horse mackerel (Trachurus trachurus) by citric and ascorbic acids

This study is aimed to investigate the effect of aqueous solutions of citric acid (CA) and ascorbic acid (AA) on the lipid stability of horse mackerel (Trachurus trachurus) fillets and whole fish during frozen storage (up to 6 and 9 months, respectively) by means of a soaking pretreatment. Best oxidation inhibition results on fish fillets were obtained when employing a 0.5% CA solution. Lower (p <0.05) peroxide (month 3), thiobarbituric acid-reactive substance (months 1 and 3) and fluorescent compound formation (month 6) values were obtained from CA-treated fish fillets than from the untreated (blank control) and water-treated (water control) fish fillets. In the case of whole fish, soaking pretreatment with a mixture consisting of 0.5% CA and 0.5% AA showed the best results in inhibiting oxidation, as lower (P <0.05) peroxide formation was observed at 6 and 9 months of frozen storage compared to the untreated or water-soaked counterparts. Advantages of both acids (CA and AA) are discussed, and further studies based on the positive role of a CA-AA mixture will be carried out to extend the shelf life of medium- and high-fat content fish species during frozen storage.