Effects of microwave-hot air combined drying on the moisture content, physical properties, flavor, and volatile components of prunes (Prunus domestica L.)

This study aimed to comprehensively investigate the effects of various microwave - hot air combined drying methods on prunes. Five drying techniques were evaluated: hot air drying (HAD), microwave - hot air drying (MHAD), hot air drying - microwave drying (HAD - MD), hot air drying - microwave - hot air drying (HAD - MHAD), and hot air drying with intermittent microwave - hot air synergistic drying (IMHAD). The results revealed that the MHAD could effectively reduce drying time by 34.2% - 87.0% compared to HAD. Compared to other methods, they also improve the color quality of the product, reduce moisture activity, and decrease the decomposition of certain volatile substances. Notably, HAD - MHAD samples had a color closer to fresh prunes, better texture, and a more favorable flavor profile with higher aldehyde, ester, and alcohol contents. In conclusion, HAD-MHAD is more suitable for prune drying than other drying methods.