Efeito da quitosana no glaciamento de filés de tilápia congelados: qualidade microbiológica, físico-química e sensorial

Abstract

In order to evaluate the effects of chitosan on tilapia fillet glacial solution on microbiological, physicochemical and sensory attributes, fresh tilapia fillets were frozen and subsequently conducted an experiment with three chitosan concentrations (0.75, 1.50). and 2.25%) and a control treatment (water glaciation), totaling four treatments, with 52 fillets per treatment. During freezing storage (0, 30, 60, 90, 120, 150 and 180 days), analyzes of pH, color and thiobarbituric acid reactive substances (TBARS) were performed. The percentage of coating incorporation, centesimal and sensory composition was analyzed. In the incorporation of the coating, a linear increase was observed, as the chitosan levels increased. The pH was significant only after 30 days, showing linear increase as the chitosan concentrations increased. For the coloration of the fillets, after 30 days, only the intensity of red decreased linearly as the chitosan increased, and after 90 days of storage, the luminosity of the fillets decreased linearly. At 90 and 120 days, a linear increase in the yellow intensity of the fillets was observed. No significant effect of chitosan on TBARS formation was observed. As the inclusion of chitosan increased, there was a linear decrease in heterotrophic bacteria in the fillets, regardless of storage time. Moisture content increased linearly while protein decreased linearly as chitosan levels increased. Ether extract and ashes were not different between fillets. In the sensorial analysis, there was no regression effect for the evaluated attributes, but the overall acceptability of the control treatment fillets was superior to the others. It was concluded that glaciers containing high concentrations of chitosan are effective to increase coating incorporation, increase fillet moisture and decrease the presence of bacteria in fillets, without greatly affecting pH or color during freezing for six months.