Effect of polyphenols green tea on microbial and chemical change rainbow trout (Oncorhynchus mykiss) during storage in ice

Effect of green tea extract and its natural antibacterial on microbial spoilage rainbow trout during ice storage was investigated. In this research fishes in whole fish form and dipped in antibacterial solutions (200، 400، 600 ppm) for 90 minutes and then were icing. During storage period (16 days)، spoilage microbial indices (TVB-N، TVC، PVC) and pH with interval of 4 days were measured and compared with control treatment. Based on obtained results in all of treatments by passing time the value of total volatile nitrogen increased significantly (P < 0/05). But this increase in treatment of 600 ppm performanced slowly. In control treatment by passing time Total viable count increased significantly (P < 0/05). Except in level of 600 ppm، other levels did not significantly different until sixteenth day in comparison with control treatment. In passage of time، Psychotroph viable count (PVC) in all of treatments was increased while control treatment in twelfth day and levels of 200 and 400 ppm in final period storage time were aggressive allowable content but 600 ppm level in final period was lower than allowable content (6/89±0/15 log cfu/gr). The value of pH was increased in all of treatments. Obtained results showed that green tea extract with dipping whole fish in consternation of 600 ppm was suggested for retardation of microbial spoilage in rainbow trout during storage in ice.