Effects of four drying methods on the quality, antioxidant activity and anthocyanin components of blueberry pomace

Abstract

Abstract The effects of drying on the quality, antioxidant activity and anthocyanin components of blueberry pomace were investigated using hot air drying (HAD), freeze-drying (FD), microwave vacuum drying (MVD) and microwave freeze vacuum drying (MFD). The quality, antioxidant activity, and individual anthocyanin compositions of blueberry pomace were evaluated and compared with the non-dried control. MVD produced the highest levels of total phenols, total anthocyanins, total sugars and color values in blueberry pomace while HAD gave the lowest. The ABTS + and DPPH radical scavenging abilities of blueberry pomace were significantly high when MVD was used. Moreover, FD, MVD, and MFD resulted in the retention of significantly more anthocyanin species than HAD as determined by HPLC coupled to the mass spectrometer. Overall, MVD proved to be the best technique for preservation of antioxidant capacity and natural color. Therefore, MVD of blueberry pomace can improve efficiency and productivity of the blueberry fruit processing industry while reducing the environmental burden. Graphical Abstract