Effect of different drying methods on aroma composition of blueberry powder

Effects of drying methods ( hot air drying, vacuum drying, vacuum freeze drying, and combined microwave-hot-air drying) on the aroma compositions of blueberry powder were studied by using solid-phase micro extraction ( SPME) and gas chromatography-mass spectrometry ( GC-MS) .Results showed that the main aroma components of fresh blueberry sample were alcohols and aldehydes, and the contents were 26.42% and 45.96%, respectively. Compared with fresh blueberry, the contents of some characteristic aroma compounds were significantly reduced by hot air drying. The reduction of aldehydes by vacuum freeze drying treatment was most significant, the content was only 2.22 × 107 AU.Ketone was significantly reduced by combined microwave-hot-air drying, the content was 7.96 × 106 AU. While vacuum drying retained the alcohol, aldehyde and ketone components in fresh blueberry much better, the contents were 7.83 × 107, 7.24 × 107, 4.83 × 107 AU, respectively. Considering the retention effect on color and aroma compositions, vacuum drying method was selected as the relatively suitable method, which providing theoretical reference for the optimization of blueberry powder processing.