Shelf life extension for Bluefin tuna slices (Thunnus thynnus) wrapped with myofibrillar protein film incorporated with catechin-Kradon extract

Abstract

This study investigated and determined the changes in various qualities of Bluefin tuna (Thunnus thynnus) slices that were wrapped with fish myofibrillar protein films (FMP) and stored in a refrigerator (4 ± 1 °C) for 10 days. The films were incorporated with catechin-Kradon extract (Careya sphaerica Roxb.). It was found that decreases in the redness index for the tuna slices were coincidental with increases in metmyoglobin content. Especially rapidly changes were observed in the control without wrapping. Changes in the total volatile base nitrogen, peroxide value, and TBARS were markedly observed in the samples wrapped with FMP when compared with others (P < 0.05). Slices of tuna flesh wrapped with FMP showed to have the lowest growth of psychrophilic bacteria when compared to those wrapped with the control film (LDPE) and the control sample without wrapping (P < 0.05). However, the pH of all samples fluctuated between 5.43 and 5.66 throughout the duration of storage. Increases in weight loss and hardness values were observed in all samples (P > 0.05). Sensory evaluation showed that the tuna wrapped with FMP had the longest shelf life (8 days), in contrast to the control without wrapping (2 days) (P < 0.05). Successful inhibition of microbial growth and lipid oxidation in the tuna slices was possible with FMP. Therefore, fish myofibrillar protein film incorporated with catechin-Kradon extract showed to have a beneficial effect on the quality of fresh tuna slice for the purposes of prolonging shelf life.