Abstract:The effect of temperature on the freshness and taste of Muraenesox cinereus during vacuum drying were studied. Five different drying temperatures were tested: 14 ℃ (mode I), 8 ℃ (mode II), 3 ℃ (mode III), ice-temperature (mode IV), and -3 ℃ (mode V). The results showed that the drying rate declined gradually as the vacuum drying temperature decreased, while the moisture content gradually increased. The minimum K value (freshness quality index) in the fillet dried at -3 ℃ during vacuum drying was 1.05%, which was very close to that of the fresh sample. The highest content of inosine monophosphate (IMP) (130 mg/100 g) was detected in the fillet vacuum-dried at ice-temperature, which was higher than that detected at other temperatures. For the filets vacuum-dried at -3℃, the IMP content was low, at 46 mg/100 g. In terms of free amino acid and main flavor-free amino acid, the increments for the K values of the filets dried at ice-temperature during vacuum drying were 22.61%, 22.59%, respectively, which were better than other conditions. In summary, for the five tested vacuum-drying temperatures, the freshness of the filets vacuum-dried at -3 ℃ was the best, with a lower content of flavor compounds. In contrast, vacuum drying at ice-temperature produced samples of excellent-grade freshness and a relatively high content of flavor compounds, IMP, and free amino acids.
