Impact of gliding arc plasma pretreatment on drying efficiency and physicochemical properties of grape

摘要

The effect of cold plasma pretreatment with different durations 10, 20, 30, 40, 50, and 60 s on the mass transfer rate and quality of grape fruit during hot-air drying at 60 degrees C and 1.5 m/s were studied. It was found that cold plasma pretreatment significantly increased effective moisture diffusivity, reducing the drying time and energy consumption by up to 26.27% and 26.30%, respectively. Longer exposure resulted in smaller shrinkage and higher rehydration ratio. Furthermore, plasma pretreatment resulted in improved quality of dried grapes, in particular higher total phenolic content, antioxidant activity, and vitamin C retention by up to 3.06-30.53%, 7.31-62.29%, and 17.87-168.73%, as compared to the untreated ones. Among all pretreatments, 50 s exposure was preferred due to the minimal energy consumption and the least effect on the samples color.