Effect of high pressure on K-value, microbial and sensory characteristics of yellowfin tuna (Thunnus albacares) chunks in EVOH films during chill storage

The effect of different high pressure treatments on K-value, total plate count, enterobacteriaceae and organoleptic characteristics of yellowfin tuna chunks packed in ethyl vinyl alcohol (EVOH) films during chill storage (2 +/- 1 degrees C) was studied. 50 g of fresh tuna chunks were placed in EVOH multilayer film pouches and vacuum packed for the trials. Tuna chunks were subjected to 100,200 and 300 MPa for 5 min at 25 degrees C. Control was vacuum packed tuna without pressure treatment. K value, microbiological analysis and sensory characteristics were evaluated at periodic intervals. The K-value of the samples was found to decrease with increase in pressure when compared to the control. However, K-value was found to increase in all the samples during storage. Higher pressure treatment showed a decrease in the total plate count in the samples which increased during the storage. The Enterobacteriaceae decreased with increasing pressure and during storage. Control samples were sensorally acceptable up to 20 days of storage. During the storage period of 30 days 200 MPa treated tuna chunks was found most acceptable based on above parameters. Industrial relevance: High pressure processing is a non thermal processing method which has wide applications in food industry. Fish is a highly perishable commodity and it has a limited shelf life in chill conditions. High pressure treatment has been found to effectively extend the shelf life of various products. In this study, HPP has been effectively demonstrated for enhancing the storage period of tuna at low temperature. Such studies can be commercially applied by fish processing industries to preserve the valuable catch and can enhance the marketing potential of tuna. (C) 2011 Elsevier Ltd. All rights reserved.