The synergistic effect of ultrasound and microwave on the physical, chemical, textural, and microstructural properties of vacuum fried Chinese yam ( Dioscorea polystachya )

Abstract

Both the ultrasound and microwave are emerging technology, used for enhancement of heat and mass transfer, due to their cheap, simple, and energy saving characteristics. The combined effect of ultrasound and microwave on vacuum frying of Chinese yam at various power levels were investigated. The trends of moisture removal and oil uptake were analyzed at different power combinations of ultrasound (300 and 600 W) and microwave (1,800, 2,400, and 3,000 W). The frying time was reduced from 18 to 12 m and oil uptake was decreased by 40.29%, when ultrasound and microwave powers were increased to 600 and 3,000 W, respectively. The texture, and color were found to be improved by the proper combination of ultrasound and microwave and was better at higher power levels. Lastly, the scanning electron microscopy (SEM) analysis revealed the more disrupted and porous structure when the ultrasound and microwave powers were at higher end. Practical applications The results showed that the fried chips at higher ultrasound and microwave powers gave the best result with regard to frying process and fried product qualities, owing to the consumers demand of low‐fat fried chips with better texture and color.

Effect of vacuum frying on quality attributes of pear ( Pyrus communis L) chips and blended oil

“…In comparison to the conventionally fried (175°C ± 5°C) product, pear chips obtained under vacuum frying showed a * values to be always on the lower side (Table 3 ) reiterating the advantage of vacuum frying over conventional frying. A similar observation was made during the vacuum frying of banana and Chinese yam when an improvement in color retention (lower a * value) was recorded (Chitrakar, Zhang, & Fan, 2019; Udomkun & Innawong, 2018). It may also be noted that vacuum frying resulted in lower oil uptake when compared to conventional frying.…”

Improving the drying kinetics and microstructure of vacuum‐fried ripened durian chips

“…Moreover, it can be seen from Table 3 that the VF+MWH led to significantly lower (P < 0.05) oil content compared to VF and P+VF. Related results were reported by Chitrakar et al (2019). The researcher concluded that the highest microwave power level led to more rapid heating, reduced frying time, increased rate of dehydration and minimised oil absorption.…”

“…Related results were reported by Chitrakar et al . (2019). The researcher concluded that the highest microwave power level led to more rapid heating, reduced frying time, increased rate of dehydration and minimised oil absorption.…”

“…In addition, when considering the effect of microwave heating on the VF process, there were no significant difference in the crispiness of the products using VF and VF+MWH ( P < 0.05), even though there were a lot slight increase in crispiness when MWH was utilised. Nonetheless, many investigators reported that microwave power helped create more porous and ruptured structure causing a decrease in hardness and improving the crispiness value (Chitrakar et al ., 2019). This is due to the interior structure of the puffed samples being hollow and the shell becoming very thin, which led to a lower breaking force during the texture analysis.…”

“…By frying fruits and vegetables at reduced pressure (~ 8 kPa) and below the temperatures 160–180°C range, unacceptable chemical reactions, such as lipid oxidation can be diminished (Thongcharoenpipat & Yamsaengsung, 2021), and acrylamide formation and risk of cancer can be minimised (Banerjee & Kumar, 2017). Furthermore, many researchers have considered VF for improving the product appearance and texture, maintaining the fresh flavour and curtailing nutritional losses of vitamins in fried fruits, such as bananas (Yamsaengsung et al ., 2011), potatoes (Su et al ., 2016) and Chinese yam (Chitrakar et al ., 2019). Moreover, in conjunction with freeze drying (FD), vacuum drying (VD) and VF, microwave‐assisted heating has been shown to reduce the drying time, improve efficiency of the process, and improve the product attributes (Su et al ., 2017).…”