Influence of microwave vacuum drying process parameters on phytochemical properties of sohiong (Prunus nepalensis) fruit

The microwave vacuum drying of sohiong (Prunus nepalensis) fruit was performed to study the effect of the processing parameters such as microwave power, vacuum level, and citric acid concentration on the phytochemical properties and the color of the dried fruit. The processing parameters were optimized using response surface methodology and the experiments were conducted using Box–Behnken design. The results showed that the processing parameter had a significant effect on the phytochemical properties and color change of the dried fruit. The optimization process revealed that the sohiong slices pretreated with 0.55% of citric acid concentration and dried at 400 W microwave power level, and 690 mmHg vacuum pressure resulted in high‐quality dried fruits. The total phenolic content, antioxidant activity, and anthocyanin content under optimum condition were 44.948 mg GAE/g, 89.761%, and 3.739 mg/g dry matter, respectively. Practical applications The study revealed that microwave vacuum drying conducted at a lower microwave power level and higher vacuum level (low absolute pressure) resulted in a high‐quality product with retention of anthocyanin, % DPPH scavenging activity, and phenolic components. The microwave vacuum dried fruits had high retention of color with the lowest color change value. In the presence of vacuum, the oxidation of molecules was prevented during drying resulted in dried products with higher nutritional value. The study would allow the scale‐up of microwave vacuum drying to obtain dried phytochemical compound rich products, which is of great interest to the pharmaceutical and food industry.