Study the Chemical, Physical Changes and Microbial Growth as Quality Measurement of Fish

Abstract

This study examined the effects of chilling, freezing, packaging, temperature and storage time on the physical, chemical changes and microbiological growth in barred Spanish mackerel (Scomberomorous commerson). At time 0 the free fatty acid, trimethylamine, and thiobarbituric acid reactive substances (TBARS) valueswere1.2%, 0.30 mg- N/100g and 0.17mgmalonaldehyde/kg, respectively. Total viable cell count and coli forms fecal were 4.6 and 3.3 log10 CFU/g, respectively. Barred Spanish mackerel was chilled at two different temperatures (4 and 7ºC) for6 days. Also, fresh mackerel was kept frozen up to 6 months at –10 and -18ºC. Sampling was carried out on the initial and at 1, 3, and 6 days for chilling and 0, 1, 3 and 6 months for freezing. Physical and chemical changes of the mackerel were evaluated by increasing TBARS values, trimethylamine and free fatty acid. Drip loss and Torry meter were also measured at various time intervals for six days at 4ºC, for three days at 7ºC and for 180 days at –10 and -18ºC. Shelf life was found to be 6 and 3 days for barred Spanish mackerel stored at 4ºC and 7ºC, respectively. Stored barred Spanish mackerel either at -10 and -18ºC showed longer acceptability tolerance (180 days). Generally, increasing temperature from 4 to 7ºC has led to about 50% decrease in the freshness period and shelf life. Freezing storage allowed the retention of freshness qualities of barred Spanish mackerel for extending their shelf life and the improved quality.