Drying Kinetics and Quality Characteristics of Slightly Salted Grass Carp Fillets by Hot Air Drying and Vacuum Microwave Drying

Abstract

Salted grass carp fillets were dried by hot air drying (HD, at 35 and 45°C) and vacuum microwave drying (VMD, at 1, 4, and 7 W/g) to a final moisture content. Compared with hot air drying, the vacuum microwave drying greatly reduced drying time. The rehydration rate constant of salted grass carp fillets dried by microwave vacuum drying at 7-W/g microwave intensity was significantly higher than that of the hot air drying at 35 and 45°C. Compared with hot air drying, the vacuum microwave dried samples had a higher crude fat content (dry basis). The lightness of the samples dried by vacuum microwave drying was higher, and the yellowness was lower than those dried by hot air drying. The drying methods had no significant effect on the hardness and springiness.

Keywords:

• grass carp fillets
• vacuum microwave drying
• hot air drying
• color
• crude fat content
• rehydration

Acknowledgments

The authors wish to thank the leaders and staff of Yanzhoufu Food Group Co., Ltd., Zhejiang, China, for their assistance in the project. The authors also thank China High-Tech (863) Plan under Contract No. 2011AA100802 and National Natural Science Foundation of China (No. 20776062) for financial support.