Desenvolvimento do método do índice de qualidade do peixe voador (Hirundichthys affinis, GÜNTHER, 1866) inteiro armazenado em gelo

Abstract

The flying fish is one of the resources of economic and social importance available to countries such as the Philippines, Indonesia, Peru, Barbados, Trinidad and Tobago and Brazil, but the processes related to their loss of freshness unknown. A tool to evaluate the sensory properties of fish freshness, considering specific aspects for each species, is the Quality Index Method (QIM), which provides demerit scores for the attributes of the fish as a function of the deterioration stage. The objective of this study was to develop the QIM to evaluate the freshness of the fish (Hirundichthys affinis, Günther, Günther, 1866), correlating with physical-chemical and microbiological analyzes throughout the storage period. For this purpose candidates were recruited and selected sensory judges by the Farnsworth Munsell Aroma Test and Test of 100 shades. The development of the QIM was done by means of 3 storage tests and were used flying fish specimens captured in Caiçara do Norte, RN, Brazil. Microbiological analyzes (Coliform counts at 45ºC/g, Salmonella sp/25g analysis, Coagulase positive Staphylococcus and total counts of aerobic mesophilic and psychrotrophic) and physicochemical analyzes were performed (pH measurement and determination of Total Volatile Bases and Trimethylamine). Then, a QIM scheme was developed with 11 parameters, grouped into 3 main attributes (appearance, eyes and gills) and a Quality Index that presented high linear correlation (r = 0.956) with storage time indicating loss of freshness during the days. The total count of aerobic mesophilic bacteria showed a significant increase (p = 0.009), ranging from 3.20 log CFU/g (1st day) to 5.61 log CFU/g (19th day of storage). The total count of mesophilic and psychrotrophic aerobic bacteria showed a strong and significant correlation with storage time (r = 0.705, p < 0.001 and r = 0.934 p <0.001, respectively), ranging from 3.20 log CFU/g (1st day) 5.61 log UFC / g (19th day storage) and 2.0 log UFC/g (1st day) at 8.18 log UFC/g (19th day storage), respectively. Salmonella was not detected. Coagulase positive Staphylococcus (4.0x102 CFU/g) and coliforms at 45ºC (3.6 NMP/g) were found in a 9th day storage sample. The mean values of pH with a linear and continuous increase (p < 0.001), ranging from 6.23 (1st day) to 6.88 (19th day). The mean values of TVB-N and TMA-N ranged respectively from 25.19 (1st day) to 39.42 mg TVB-N/100 g (19th day) and 6.58 (1st day) to 12.17 mg (p <0.001 and p < 0.001) with a strong and significant linear correlation (r = 0.923, p < 0.001 and r = 0.747, p < 0.001) with storage time. As averages of Thiobarbituric Acid Reactive Substances (TBARS) ranged from 0.08 (1st day) to 2.52 MA / Kg (22nd day). The Principal Component Analysis suggests that the flying fish remain with an acceptable degree of freshness for up to 9 days, considering the analyzes and ice storage conditions used in this study.