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Abstract

The study aimed to evaluate the variation of sensory, physicochemical, and microbiological quality indices with storage time of Indian mackerel preserved on ice. The research was done on Indian mackerel caught in one offshore fishing trip, stored on ice traditionally within 25 days. The quality indices were assessed and recorded on the 0, 3rd, 5th, 10th, 15th, 20th, and 25th day of the storage period. Quality Index (QI), pH, PVB-N, NH3, TMA, NPN, PV, TBA, and TPC were experimented and recorded. Data were analyzed using descriptive statistic method.  QI varied from 0-31 points. Visually significant quality changes appeared between 10-15 days of storage. The pH range was from 6.07 ± 0.02 to 7.16 ± 0.04 (P<0.05). The NH3 content was from 16.25 ± 0.04 to 119.03 ± 0.05 percent; the TVB-N value was from 119.03 ± 0.05 to 152.57 ± 2.89 mg per 100g; the TMA value ranged from 6.07 to 20.39 mg per 100g; the NPN content was from 0.24 to 0.77 percent. The PV range was 0.91 ± 0.06 to 5.14 ± 0.09 meq per kg, while TBA was from 63.01 ± 0.51 to 571.87 ± 3.50 μmol per kg. The TPC ranged from 12.4 to 4.1x105 CFU per g. All indices showed a linear increment relationship with time of storage. QI scheme suggested for Indian mackerels was 0-15 QI points, and the estimated shelf-life was ten days for whole fish storage on ice. The pH and some nitrogen related quality indices (NH3, TVB-N, and NPN) had a slight relationship to the acceptable sensory quality limit while the lipid-related index did not. They could be indicators or estimators to spoilage of fish under the studied conditions. The TPC showed similar to prior studies. Indian Mackerels were found to have  10-15 days shelf-life under the studied storage conditions, which was not enough for offshore fishing time, but it could be acceptable in VietNam fishing industry condition. The sensory, physicochemical, and microbiological indices were extensively assessed and formed a foundation to further research on the preservation and quality evaluation of the Indian mackerels on the Vietnamese market.