Radio frequency combined hot air (RF-HA) drying of tilapia (Oreochromis niloticus L.) fillets: Drying kinetics and quality analysis

Hot-air assisted radio frequency (RF-HA) heating was utilized for tilapia fillets drying to achieve rapid, uniform drying and improved sample physical properties. Effects of sample thickness (5, 8 and 10 mm) and with or without wrapping material (skin or gauze) were investigated under both HA and RF-HA drying treatments. The drying characteristics and quality parameters of tilapia fillets in hot air (HA) and RF-HA drying were then determined. Results show the drying rate of RF-HA drying is 1.1-1.4 times of that of HA drying for tilapia samples with different thicknesses. RF-HA dried samples are with higher rehydration rate and lower volume shrinkage rate, especially for fillets with larger thickness. The wrapped gauze did not show significant influence on the color of tilapia sample in RF-HA drying but improved the rehydration rate, while the samples with preserved fish skin resulted in a lower overall quality under both HA and RF-HA drying treatments. Page model and Henderson-Pabis models were suitable to be used describing the drying kinetics of RF-HA drying and HA drying tilapia, respectively.

Automated summary

The study showed that RF-HA drying has a faster drying rate and better sample quality compared to HA drying. The use of gauze wrapping can improve the rehydration rate, while preserving fish skin may result in lower overall quality.