干燥方式对梨枣粉品质特性的影响

Effect of Drying Treatment Methods on the Quality Properties of Pear Jujube Power

研究热风干燥、微波干燥、真空干燥及真空冷冻干燥4种干燥方式对梨枣粉理化特性及其抗氧化活性的影响。结果表明:对维生素C含量的影响依次为真空冷冻干燥>微波干燥>真空干燥>热风干燥,对总糖含量的影响无显著性差异,使可滴定酸含量降低。不同干燥方式对梨枣粉中总酚、总黄酮含量有显著性影响。真空冷冻干燥梨枣粉的抗氧化活性明显优于热风干燥及真空干燥。热风干燥、真空干燥、微波干燥及真空冷冻干燥梨枣粉中酚酸类物质总和分别为39.91,87.46,92.56,110.82 mg/kg。综合来看,真空冷冻干燥技术不仅保留梨枣粉的理化特性,而且利于保持梨枣粉的抗氧化活性。

The effects of four drying methods including hot air drying, microwave drying, vacuum drying, vacuum freeze-drying on physicochemical properties and antioxidant activity of pear jujube power were investigated. Vacuum freeze-dried pear jujube power exhibited the largest Vc and best antioxidant activity followed by those dried by air dry- ing, microwave drying, vacuum drying. Pear jujube powers showed no remarkable change in total sugar after different drying, but statistically significant difference on total phenolic and total flavonoid content. All of the four drying methods could result in a decrease in the titratable acidity content. The content of total phenolic acids of pear jujube powers after drying were 39.91,87.46,92.56,110.82mg/kg, respectively. The results collectively indicate that vacuum freeze-drying can result in both better product physicochemical quality and antioxidant activity and is therefore suitable for industrial-scale production of dried jujube products.