Abstract: The contents of taste components in the belly, dorsal meat and red meat of grass carp frozen by different methods: quick freezing at ?40 ℃, liquid alcohol freezing at ?20 ℃, and static air freezing at ?20 ℃ were determined and compared by high performance liquid chromatography (HPLC), amino acid auto-analyzer and electronic tongue. The lactic acid content of fish meat was also determined. The results were obtained as follows. The freezing methods had an influence on fish freshness and taste components. The freezing rate was positively correlated with the contents of inosine monphosphate (IMP), adenosine monophosphate (AMP) and total free amino acids, whereas it was inversely correlated with lactic acid, insoine (HxR) and hypoxanthine (Hx). Fish samples frozen by the first and third freezing methods showed the lowest and highest K values (freshness index) after 3 d of frozen storage at ?20 ℃, respectively. Of the three meats, red meat contained the highest contents of IMP and AMP but lowest contents HxR and Hx, which led to poor taste and freshness. The K values of red meat frozen by three freezing methods were 28.99%, 40.92%, and 46.58%, respectively. The contents of free amino acids in belly meat were similar to those of dorsal meat, but higher than those of red meat. Notably, red meat was significantly richer in asparagic acid and glutamate as well as lactic acid than belly meat and dorsal meat, and the lactic acid content of red meat was greatly affected by the freezing methods. The different parts of fish meat and fish samples frozen by the different freezing methods were clearly distinguished with an electronic tongue.

Key words: grass carp, freezing methods, ATP-related compounds, free amino acids, lactic acid