关键词: 罗非鱼片, 冰温干燥, 真空压力, K值, 游离氨基酸, 复水率, 色泽

Abstract:

In this study, tilapia fillets were freeze-dried under three different vacuum pressures, 700—800, 1300—1400 Pa
and 1900—2000 Pa and the drying rate, rehydration rate, color, K value as an index of freshness and free amino acid of dried
samples were measured to evaluate the effect of vacuum pressure on the quality of freeze-dried tilapia fillets. The results
showed that the drying rate of fillets at 700—800 Pa was the fastest with 20.8% water content after drying for 24 h, and the
rehydration rate also was the highest with a value of 43.27%. The total content of free amino acids at 1900—2000 Pa was the
highest, followed by 1300—1400 Pa, and 700—800 Pa. In addition, the K values at three different vacuum pressures were
close, within freshness grade 1, indicating little impact of vacuum pressure on the freshness of dried tilapia fillets.

Key words: tilapia fillets, ice-temperature drying, vacuum pressure, K value, free amino acid, the rehydration rate, color