Determination of some quality changes of rainbow trout (Oncorhynchus mykiss) fillets applied green tea added edible coating

In this study, trout fillets were covered with edible coating made from protein hydrolyzate and green tea extract and their quality changes were investigated for 13 days under cold storage (4 ± 1 °C) conditions. A total of 10 kg of rainbow trout ( 226.40 g), powder protein hydrolyzate and green tea extract were used as working material. During the experiment, analyzes were conducted to determine the biochemical changes in K (control group) and HYK (group coated with mixture of protein hydrolyzate and green tea extract) groups and statistical difference in crude protein (%) content was found (p<0.05). Total volatile basic nitrogen (TVB-N) values increased during the storage period, and also these values were found as 16.81 and 48.33 mg/100g in K group as 17.51 and 30.82 mg / 100g in HYK group, respectively on the 1st and 9th day. According to the microbiological analysis results, the fresh trout fillet and 1st day values of K and HYK groups were determined as <1.47 log cfu/g. Bacterial counts increased during the storage period but these values in coated group were found lower than control group. In terms of sensory evaluation, K and HYK groups were found below the limit value of 4 points at 5th and 13th day, respectively. According to the results of study, shelf life of coated group (11 days) was found three times higher than the shelf life of control group (3 days).