Abstract:

In order to find out appropriate sterilization agents and methods which could be used to improve the fresh tilapia fillet quality, several kinds of bactericides were compared in this study. The effects of food grade hydrogen peroxide (H2O2), sodium chloride (NaClO), chlorine dioxide (ClO2), chitosan and ozone (O3) water on total number of bacteria, color and sensory quality were compared. The optimal treatment with 1 g/L H2O2 was achieved by 5 min immersion, while the treatment with 100 mg/L NaClO only cost 2 min. When treated with 150 mg/L ClO2 for 10 min, the bacterial number of the fillet was reduced by 90.7%. A period of 5 min was found to be enough for the treatment with 2 g/L chitosan, and the optimal treatment procedure with 5 mg/L ozone water was 10 min immersion. However, compared with ozone water, all of H2O2, NaClO, ClO2 and chitosan had worse influences on sensory quality (color and odor) of tilapia fillet. Therefore, the 10 min treatment with 5 mg/L ozone water was selected. The ozone water treatment not only effectively reduces bacterial number but also has little influence on tilapia fillet quality, so it is an ideal bactericide for tilapia fillet processing.

Key words: fresh tilapia fillet, pretreatment, colorimeter, sensory evaluation