Research Article: Determination of freshness quality changes using selective methods: A comparative study for eclipse parrotfish (Scarus russelii) and spangled emperor (Lethrinus nebulosus)

The present study was carried out to determine freshness quality and remaining storage time of eclipse parrotfish and spangled emperor stored in ice on days ۰, ۲, ۳, ۵, ۷, ۹, ۱۲, ۱۵, ۱۹ and ۲۱ using selective methods. A score of ۱۱-۱۲ coincided with the level at which the fish were considered unacceptable by a sensory panel of six experienced assessors. The demerit score of eclipse parrotfish and spangled emperor increased linearly (R۲=۰.۹۵۶۳ and ۰.۹۶۲۴, respectively) with storage time. The limit for acceptability of eclipse parrotfish and spangled emperor stored in ice was ۹ and ۱۹ days respectively. Total volatile base nitrogen value (۴۵.۸۷±۱.۱۰ mg/۱۰۰g) for parrotfish stored in refrigerator exceeded limit of acceptability at the time of sensory rejection (۹th day) while the value (۵.۹۳±۰.۲۸ mg/۱۰۰ g) for spangled emperor was remained below the limit of acceptability after ۹ days and increased to ۵۴.۹۶±۱.۸۰ mg/۱۰۰g at the ۱۹th day. The pH for both fishes showed significant (p<۰.۰۵) increases during the storage. Total viable count in spangled emperor analyzed were found to be below the acceptability limits (۶ log۱۰ cfu/g) by ۱۵ days while maximum level of acceptability of eclipse parrotfish was until ۷ days. Shelf-life of both fishes was different. Sensory score, value of TVB-N, pH and TVC provide evidence that the limit for acceptability was ۷ days for eclipse parrotfish and ۱۵ days for spangled emperor stored at ۰ - ۲۰C.

Keywords:

Eclipse parrotfish , Freshness quality , Spangled emperor