The Role of Processing Conditions on the Color and Antioxidant Retention of Jet Tube Fluidized Bed-Dried Blueberries

摘要

Jet tube fluidized bed drying was investigated as a means of rapidly generating shelf-stable and high-quality sweetened and non-sweetened blueberries. Sugar-infused and noninfused scarified Rabbiteye blueberries (Vaccinium ashei 'Brightwell') were dried at 99, 107, and 116°C. Prior scarification of the blueberry surface aided in decreasing the drying time. Increased lightness (L') values were most notable at higher drying temperatures for sugar-infused blueberries, suggesting loss of pigments. Total monomeric antho-cyanins level, initially 7.65 mg cyanidin-3-O-glucoside equivalents (C3G eq)/g extract, decreased as drying temperature increased and ranged between 4.07 down to 1.51 mg C3G eq/g extract for dried blueberries. The total phenolics content increased with drying for noninfused blueberries, with highest levels of 31.6 mg gallic acid equivalents (GAE)/g extract for samples dried at 107°C. With the exception of sugar-infused berries dried at 107 and 116°C, the dried blueberries maintained or demonstrated slightly increased hydrophi-lic oxygen radical absorbance capacity (H-ORAC_(FL)) values, indicating that their antioxidant capacity was retained upon drying. Blueberries dried at 107°C possessed the greatest preference scores and best retention of blueberry flavor and required a relatively short drying time.