Development and Application of the Quality Index Method (QIM) for Farmed Tambaqui (Colossoma macropomum) Stored Under Refrigeration

Abstract

This research aimed to assess the freshness of farmed tambaqui (Colossoma macropomum) eviscerated and stored in ice for 30 days. The changes observed in the fish over storage were monitored through sensory evaluation Quality Index Method (QIM), pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and microbiological analyses (coagulase-positive staphylococcus, Salmonella spp., coliforms at 45C, and mesophilic and psychrotrophic bacteria counts). The Quality Index (QI) showed a linear increase, ranging from 0 (maximum freshness) to 34 (total loss of freshness), with a strong correlation (R2 = 0.988) with storage time. The microbiological analyses showed that the psychrotrophic bacteria count went over the recommended limit after the 26th day. TVB-N ranged from 4.01 to 15.92 mg/100 g; pH, from 6.01 to 6.57; and TBARS, from 0.01 to 0.14 mg MDA/kg between the 1st and 30th days of storage. The sensory, physicochemical, and microbiological analyses established that eviscerated tambaqui stored in ice is appropriate for consumption up until the 22nd day. Practical Applications The QIM takes into account the diversity among species and defines the sensory quality parameters for fish freshness. Sensory analysis has been shown to be an important tool to assess sensory quality of fresh fish and is largely used by sanitary inspection agencies. The QIM established that eviscerated tambaqui (C. macropomum) stored in ice at 0C remained proper for consumption until the 22nd day. The results of the application of QIM to marketed fish species can establish the product's shelf life which is a very important for the industry and for consumers. QIM: Development and Application of a Sensory Protocol for Farmed Tambaqui (C. macropomum).