Evaluation of Quality and Shelf Life of Two Commercially Important Fish Species Viz., Tiger Tooth Croaker (Otolithes ruber Bloch and Schneider) and Flathead Grey Mullet (Mugil cephalus Linnaeus) in Iced Conditions

Abstract

A study on the quality parameters to assess the shelf life of two commercially important species viz. Tiger tooth croaker and Flathead Grey mullet from different aquatic environments was carried out under iced conditions. Croaker, a marine species and grey mullet from brackish water sources was used for the study. Biochemical quality indices like non-protein nitrogen, total volatile basic nitrogen, peroxide value and free fatty acids were assessed. Changes in moisture, pH and K-value were also determined. For croaker, FFA values increased from the initial 2.2–20.1 % on 15 days of storage in ice, whereas in case of mullet it reached 17.9 % during the same period. During the same period the pH values showed an increase from 6.81 to 7.88 and from 6.68 to 7.53 in case of croaker and mullet respectively. TVBN and PV increased throughout the period of storage and the former crossed the limit of acceptability of 30 mg/100 g by 15 days in ice. The sensory evaluation based on demerit score system was carried out which showed that the species retained the high quality shelf life characteristics for 5 days in case of croaker and 7 days in case of mullet. However both the species remained in acceptable condition for a period of 13 days. Freshness index K-value for both species complemented the sensory evaluation scores.