Abstract
Ornate emperor (Lethrinus ornatus) stored under refrigeration (5 °C) in a combination of dry ice and wet ice at an optimum level of 1 : 0.2 : 0.5 (w/w/w) were found to be sensory acceptable up to 12 days without re-icing. Samples stored in wet ice at 1 : 1 (w/w) were acceptable for only 8 days. Total bacterial load ranged from 104 to 106 cfu/g, while total psychrotrophs increased 6 log cycles. Lactic acid bacteria count increased 3 log cycles and H 2S producers increased 4 log cycles. Micrococcus constituted 79% of the flora in fresh fish. Micrococcus (40%) was also the dominant flora in the combination pack, while Alcaligenes (26%) was dominant in wet ice pack. TVB-N content did not exceed the limit in any of the packs. Free fatty acid and hypoxanthine contents reached to 18.27% as oleic acid and 13.36mg/100g, respectively at the end of storage. Total fat was very low (0.26%), but total protein was high (25.5%) in the raw fish. During storage in the combined ice pack, there was a gradual reduction in the salt soluble proteins from 77.1 to 62.9%. Raw fish contain health beneficial ω-3 fatty acids particularly docosahexaenoic acid (DHA) at a level of 7.15% out of total fat. The loss of this essential fatty acid during storage in the combined pack was only 61%, while in the control pack, the loss was high (88%).
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