Qualidade da Tilápia-do-Nilo Submetida ao Extrato de Tingui

Abstract

This research was divided into two stages. In the first stage its objective was to monitor the pre rigor and rigor mortis after the slaughter of Nile tilapia, previously submitted to extract Tingui and in the second stage the objective was to track changes in post mortem of Nile tilapia previously submitted to Tingui extract. In the first phase were carried out two experiments using 54 fishes weighing on average 685 ± 185.4 g, distributed in 18 boxes, forming a completely randomized design with six treatments: TO - control (without exposure to Tingui extract), T1, T2, T3, T4 and T5 - 10, 20, 30, 40 and 50 minutes of exposure to Tingui extract, respectively, and the other one with 54 fishes weighing an average of 400.47 ± 62.23 g, submitted to treatments: TO -control (without exposure to Tingui extract), T1, T2, T3, T4 and T5 - 0.5, 1, 2, 4 and 6% (v / v), respectively. In the second stage we used 48 specimens of Nile tilapia, weighing on average 643 ± 164 g. They were randomly divided into 12 boxes of 50 liters, and remained there for 40 minutes, being applied three treatments, which consisted of adding of chlorine at concentration of 5 ppm, Tingui extract to 4% (v/v) + 5 ppm chlorine and Tingui extract to 4% (v/v), respectively. In the first stage in both experiments, the muscle pH decreased and rigor mortis was increased during ice storage. However, the lower values of rigor mortis were observed for fishes exposed to Tingui extract between 20 and 30 min and in the concentration from 1 to 2%. In the second stage during the storage period, the pH, the rigor index, the microbial load and total volatile nitrogen bases have grown and the sensory evaluation scores decreased. However, there was no rejection of the fish and nor the values of volatile bases and microbial load exceeded the acceptable values by Brazilian law for 21 days of storage.