Effect of Green tea and Gooseberry extracts in improving quality of Indian White Prawn (Fenneropenaeus indicus) during chilled storage and assessment of synergistic effect of their combination

Abstract- Fenneropenaeus indicus (Milne Edwards, 1837) popularly known as Indian white prawn is an important species in the rice field shrimp farming (pokkali) of the Kerala coast of southwest India and an important species for both offshore fishing and in pond culture especially in India, Bangladesh, Malaysia, Thailand, Indonesia and the Philippine. However, it is one of the most perishable items due to lipid oxidation, biochemical degradation followed by microbial spoilage and melanosis problem which makes it unacceptable to the consumer in a short span of time.
Growing health concern among the new generation consumers and increased regulatory awareness has led towards the use of natural antioxidant and antimelanogenic agents instead of synthetic artificial additives. Hence, recent research is looking forward to find natural source to extend the products shelf life. Green tea and amla are well known in this field due to their potent antioxidant nature. The effect of the antioxidant activity of the green tea extract, amla extract and their three different combinations (GTE: AE= 2:1, 1:2, 1:1) was investigated on chilled Indian white prawn stored at 4°C for 28 days.
Green tea and amla fruit ethanolic extracts were subjected to different antioxidant assay viz. DPPH scavenging ability, FRAP assay, Total phenolic content (TPC), total flavonoid content (TFC) and total antioxidant capacity (TAC), PPO inhibitory ability and phytochemical screening to evaluate the potentiality of the extracts. Present study found both the extract possess significant level of phenolic and flavonoid content (p<0.05). Percentage of free radical scavenging ability and ferric reducing power were found to be more or less same in green tea extract and amla extract (p>0.05).
Biochemical (TVB, TMA, FFA, and PV) analyses, microbiological analyses (TVC), assessment of melanosis formation and sensory analyses were performed in order to evaluate the quality retardation and to determine the shelf-life of refrigerated and extract treated shrimp.
Present study also found Amla and green tea ethanolic extract to be potent to retard quality loss as well as to maintain sensory quality compare to control group (p<0.05). Nevertheless, melanosis formation was more in untreated group and sensory analysis could find the deterioration in untreated group was faster than treated counterparts (p<0.05). The result showed that the use of green tea extract, amla extract and their 2:1 (GTE: AE) combination gave the best result (p<0.05) followed by other two combinations of 1:1 and 1:2 (p>0.05) in order to retard the quality loss of chilled stored Indian white prawn for 28 days as well as delay the formation of melanosis and improve the sensory quality.