真空冷冻和热风干燥对蓝莓品质的影响

研究真空冷冻干燥和热风干燥处理对蓝莓品质的影响。采用电阻法测定蓝莓的共晶点和共熔点，并绘制了蓝莓冻干曲线；从干燥后蓝莓的微观结构、复水比、色泽、质构、VC、总花色苷和总酚等指标比较真空冷冻和热风干燥蓝莓产品的品质。结果表明：蓝莓的共晶点为－33 ℃，共熔点为－30 ℃；真空冷冻干燥蓝莓复水性好，且果实中VC、总花色苷和总酚的含量分别为5.52 mg/100 g、1.55 mg/g和3.55 mg/g，显著高于热风干燥的产品。因此，真空冷冻干燥在保持蓝莓复水性、感官品质和活性成分等方面比热风干燥具有明显优势。

Effects of Vacuum Freeze-Drying and Hot-Air Drying on the Quality of Blueberry Fruits

The effects of vacuum freeze-drying and hot-air-drying on the quality of blueberry fruit were investigated in thisstudy. The eutectic point and consolute point of blueberry were determined using the resistance method to analyze freezedryingcurve. Ultrastructure, rehydration rate and the contents of vitamin C (VC) and anthocyanin of hot-air and vacuumfreeze dried blueberry fruits were also investigated. The results showed that the eutectic and co-melting temperatures ofblueberry were －33 and －30 ℃, respectively. Compared with hot-air drying treatment, vacuum freeze-drying maintaineda higher rehydration capacity. The contents of VC, anthocyanin and total phenolic in vacuum freeze dried blueberry were5.52 mg/100 g, 1.55 mg/g and 3.55 mg/g, respectively. Therefore, vacuum freeze-drying has the advantages over hot-airdrying in maintaining the rehydration characteristics, sensory quality and active ingredients of dried blueberry fruit.