Synergistic effects of ultrasound and microwave on the pumpkin slices qualities during ultrasound-assisted microwave vacuum frying

The aim of this study was to investigate the effect of the ultrasound-assisted microwave vacuum frying (USMVF) technology on the quality parameters of pumpkin slices. Pumpkin slices fried for 15 min by different frying methods, such as USMVF, microwave-assisted vacuum frying (MVF), and vacuum frying (VF), were compared in terms of parameters such as moisture content, oil content, color, texture, and microstructure. During the frying process, the effect of microwave powers (600 W, 800 W, and 1,000 W) and ultrasound powers (0 W, 300 W, and 600 W) was evaluated and compared with the conventional VF. The results showed that the application of ultrasound lowered the moisture content significantly (p < .05) in comparison to MVF and VF samples. The application of ultrasound also positively affected the oil content (low oil absorption) and texture (better crispness) of USMVF samples. Cellular structure of pumpkin chips was also preserved well when ultrasound-assisted frying process. Color was not significantly influenced by applying ultrasound. In summary, the microwave and ultrasound applied in the VF process showed a synergistic effect in promoting the quality parameters of pumpkin chips. Practical applications The results showed that the application of ultrasound lowered the moisture content significantly in comparison to microwave-assisted vacuum frying and vacuum frying (VF) samples. The application of ultrasound also positively affected the oil content (lower oil absorption) and texture (better crispness) of ultrasound-assisted microwave vacuum frying (USMVF) samples. Microstructure of pumpkin chips was also preserved well when ultrasound-assisted frying process. Color was not significantly influenced by applying ultrasound. In summary, the microwave and ultrasound applied in the VF showed a synergistic effect in promoting quality parameters of pumpkin chips.