Influence of Fat Content on the Salt-Ripening Process of the Peruvian Anchovy (Engraulis ringens)

Abstract

The study evaluated the influence of fat content on the salting ripening process of Peruvian anchovy (Engraulis ringens) at an industrial scale. Two batches of two tonnes each of E.ringens were processed, with heads and viscera removed before placing the fish in barrels with salt for ripening. The first batch contained 9.0 % fat, and the second 6.8 %. Sensory qualities were evaluated and the documented ripening times revealed no significant differences between batches; however, the higher-fat batch exhibited a slower decrease in water activity (aw) and reached sensory ripe slightly later than the batch with lower fat content. Physico-chemical analyses within each batch showed average increases in the proteolysis index (PI), total volatile basic nitrogen (TVB-N), and trimethylamine (TMA), but no significant differences between batches. The high variability inherent to industrial-scale processing limited the establishment of a direct correlation with fat content. Regarding amino acid composition, the initial histidine content in raw fillets was 2.1 g.100 g-1, representing 81 % of free amino acids; however, during salting, most histidine diffused into the brine, leaving only 0.3 g.100 g-1 in the ripened product. Ripening led to an increase in free amino acids, particularly leucine, lysine, and glutamic acid, while the total amino acid content in the muscle decreased due to osmotic processes, salt-induced protein solubilisation, and proteolytic activity. Histamine levels in both batches remained below 50 mg.kg-1 at the end of ripening, complying with food safety standards.