# Development and Application of the Quality Index Method for Ice-Stored King Weakfish (Macrodon ancylodon)

## TL;DR

This study develops a freshness evaluation method for king weakfish stored in ice, combining sensory and chemical analyses to estimate shelf life.

## Contribution

The paper introduces and applies a Quality Index Method (QIM) specifically for king weakfish freshness assessment during ice storage.

## Key findings

- The QIM scores increased linearly with storage time, showing strong correlation (R2 = 0.9868).
- Fish freshness was maintained for up to 11 days in ice storage based on microbiological and chemical indicators.
- Putrescine, cadaverine, and spermidine were identified as potential freshness indicators.

## Abstract

The freshness of raw fish has become one of the industry’s and consumers’ main concerns regarding quality, safety, and shelf-life estimation. To determine the freshness of the king weakfish (Macrodom ancylodom), the quality index method (QIM) was employed for sensory analyses, along with the assessment of proximate composition, pH, total volatile bases (TVB-N), thiobarbituric acid reactive substances (TBARS), biogenic amines, fatty acids, texture, and microbiological parameters. The results show that the QIM obtained over the storage period exhibited a linear increase, ranging from 2 to 21 demerit points, with a high correlation (R2 = 0.9868) among the data. The microbiological results indicated an increase in the counts of psychrotrophic and mesophilic bacteria throughout the storage period. TVB-N values ranged from 11 to 28 mg/100 g, and TBARS values ranged from 0.235 to 0.298 mg MDA/kg when stored in ice. The presence of putrescine, cadaverine, spermidine, and toxic volatile compounds was a potential indicator of fish freshness. Based on the correlation between the methods considered indicators of freshness and quality, it can be concluded that the king weakfish maintains its commercial stability for up to 11 days when stored in ice.