Enhancement of the storage quality of frozen bonito fillets by glazing with tea extracts

The effect of glazes of various tea extracts upon the storage stability and the quality of bonito fillet and its associated storage deterioration are examined. Fresh bonito fillets were glazed using either water or tea extracts, which had been allowed to ferment to various extents. Ice glazing enhanced the storage quality of the bonito fillet as compared to an untreated sample. Some of the tea-glazing treatments did provide some degree of protection, although some did not. The antioxidant activity of a particular species of tea as impacted upon bonito flesh related substantially to the extent of natural fermentation of the tea species used for glazing. Green tea and Pouchong tea afforded better protection than black tea for both lipid oxidation and protein oxidation within bonito flesh, therefore they maintained a better quality of preserved bonito fillet. The combination of a glazing treatment and the application of green or Pouchong tea extract at a 5% concentration was able to greatly increase the storage quality of the frozen bonito fillets. (C) 2004 Elsevier Ltd. All rights reserved.