Avaliação da alta pressão hidrostática sobre a qualidade de filé de sardinha brasileira

Abstract

Sardine is one of the main genera of fish caught in the world, and in Brazil, and especially in the state of Rio de Janeiro, the Brazilian sardine (Sardinella brasiliensis) represents the most important species marketed. Although it is widely consumed in the country, the Brazilian sardine has a short shelf-life in refrigerated fresh form, with undesirable progressive changes even in that period. Despite its commercial and social importance, no innovative process aiming an increased shelf life has been developed in recent decades. Therefore, the objective of this thesis was to evaluate the effects of the High Hydrostatic Pressure (HHP) on sardine quality. Although the use of this technology in fish is already done on an industrial scale worldwide, desirable or adverse effects may occur at fish-specific intensities, and there is no relevant scientific information on sardines. Chapter I introduces sardine and HHP. Chapter II further discusses on the effects of HHP on fish in general, bringing the main results of scientific research on the central issue to discussion. In Chapter III experimental results of the application of 100, 200, 300 or 400 MPa for 0 or 15 min in sardine are presented. The increase in HHP intensity caused progressive bleaching and a slight increase in pH. The shear force and drip loss exhibited variable effects according to HHP level. It was concluded that the treatments 300 MPa / 0 min, 400 MPa / 0 min, 200 MPa / 15 min and 300 MPa / 15 min exhibited effects of greater similarity with the control (fresh, non-pressurized sardines). Chapter IV evaluated the effects of the HHP levels on the physical and chemical quality of sardines during storage (21 days, 5 ° C). It has been shown that HHP exhibits potential to: 1) attenuate shear force reduction and increase in pH occurring during storage; 2) reverse, even partially, the increase of L * and reduction of a * caused by the HHP itself on day 0; 3) stabilize drip loss at 300 Pa / 15 min; and 5) cause no catalysis of protein or lipid oxidations, especially up to 14 days of storage. It was concluded that there are no limitations for the processing of sardines, at the levels evaluated, regarding the main effects on physical and chemical quality. Chapter V evaluated the effects of HHP on formation of nitrogenous compounds (TMA and N-TVB) and degradation of nucleotides, traditional indicators of fish degradation. It was observed that HHP inhibited the formation of TMA and N-TVB, modified the degradation profile of nucleotides, promoted accumulation of IMP and inhibited the formation of HxR and Hx, consequently delaying the increase of K value (mainly 300 MPa / 15 min). These results suggest that APH exhibits potential for quality stabilization over the storage period.