Effect of incorporation of green tea extract in icing medium on the quality and shelf life of Nemipterus japonicas (Bloch, 1791) in chilled storage

The present study was aimed at investigating the effect of inclusion of green tea leaf (GTE) extract (at 3 and 6% levels) in the icing medium employed during the chilled storage (2±1°C) of Japanese threadfin bream Nemipterus japonicus .Fish stored in normal ice (NI)was treated as control. Changes in microbiological, biochemical and sensory quality characteristics were monitored during the period of storage. Multivariate comparison was performed using principal component analysis (PCA) for the mean sensory, microbiological and chemical attributes. Samples stored in normal ice (NI) had only 8 days shelf life whereas both 3% GTE and 6% GTE stored samples had a shelf life of 16 days. From an economic point of view 3% GTE can be adopted for preservation of fish and there was no significant difference in the parameters between 3 and 6% GTE levels. Visualisation by PC plots clearly separated the investigated samples according to storage conditions, thus indicating the importance of GTEI treatment. The present study indicated that the application of GTE in ice (GTEI) is a promising technique to increase the shelf life of N.japonicus in chilled condition and hence the technique can be commercially exploited. Keywords: Chilled storage, Green tea leaf extract, Nemipterus japonicus , Principal component analysis, Shelf life