The effects of thermosonication on quality parameters of cashew apple nectar: An optimization study for processing conditions

•Change in temperature affected ΔE* of the nectar more than UED.•The increase in UED affected PPO inactivation more than at the low temperatures.•Effect of UED on AA content of nectar differs based on the treatment temperature.•Optimum parameters were determined as 300 J/g and 60 °C for high quality nectar. Thermosonication is an alternative treatment to process juices avoiding the thermal degradations promoted by conventional heat treatments. Therefore, the aim was to determine the optimal parameters of thermosonication to treat cloudy cashew nectar to inactivate polyphenol oxidase-(PPO), while promoting the maintenance of some bioactive compounds. The effects of ultrasound energy density-(UED) and temperature on PPO inactivation and some quality properties such as total phenolic-(TP), ascorbic acid-(AA) and color difference-(ΔE*) were determined and revealed by mathematical models. The increase in only one parameter (temperature or UED) caused a rise in PPO inactivation, while the other quality properties were constant. The same concentration of TP was obtained (426 mg/L) with high UED - low temperature (25 °C–595 J/g) or low UED – high temperature (121 J/g–57 °C). The highest levels of PPO inactivation, TP and AA content (1171 mg/L) were provided when treatment of approximately 350 J/g UED was performed at a high temperature (65 °C). An increase in temperature affected ΔE* more than UED, the highest color change was observed at 598 J/g and 45 °C. Thus, the optimal parameters of thermosonication were determined as 300 J/g and 60 °C.