Effect of three kinds of drying methods on the flavor substances of tilapia fillet

Tilapia fillet was used as sample, the changes on fresh, volatile compounds, organic acids and mineral salt ions of fresh fillet with three kinds of drying methods (ice-temperature vacuum drying, vacuum freeze drying, hot air drying) using high performance liquid chromatograph, gas chromatograph-mass spectrometer and atomic absorption spectroscopy were studied. The results showed that:K value of fresh fillet was 2.83%. In the ice-temperature vacuum drying fillet and vacuum freeze drying fillet, it was 3.87% and 4.29%, respectively, twithout significant difference. Compared with other samples, K value in hot air drying fillet was higher, it was22.69%. Meanwhile inosinic acid (IMP) content in ice-temperature vacuum drying sample was obvious higher than the other two drying samples. In the Tilapia fillet, carbonyl compounds played main role on the flavor.There were detected 11, 8, 10, 13 kinds of carbonyl compounds separately which the total percentage contents were 36.36%, 14.33%, 20.03% and 28.60% in fresh sample, ice-temperature vacuum drying sample, vacuum freeze drying sample and hot air drying sample. At the aspects of organic acids and mineral salt ions, organic acids content was increased, while mineral salt ions was decreased in drying samples compared with fresh sample, but the change was minimum in ice-temperature vacuum drying sample. Several factors above combined, it can be concluded that the effect of ice-temperature vacuum drying was superior to vacuum freeze drying and hot air drying.