不同干燥方式对枣粉品质的影响

通过对变温压差膨化干燥、真空干燥、热风干燥和真空冷冻干燥4 种干燥方式所得枣粉的物理特性和营养成分的分析测定，研究不同干燥方式对枣粉品质的影响。结果表明：在物理特性方面：真空干燥和真空冷冻干燥枣粉呈现较好色泽，真空冷冻干燥枣粉溶解性差于其他3 种枣粉，吸湿性无明显差异，变温压差膨化干燥和热风干燥枣粉复水性较好，真空冷冻干燥枣粉的粒径和堆积密度最小；在营养成分方面：4 种枣粉的营养成分较鲜样均有不同程度的降低，变温压差膨化干燥和真空冷冻干燥枣粉的还原糖和总糖含量相对较高，真空干燥枣粉总酸含量最高，真空干燥和真空冷冻干燥枣粉的VC和黄酮含量较高，真空冷冻干燥和变温压差膨化干燥枣粉的环磷酸腺苷含量稍高于其他两种。枣粉的综合评分结果显示，真空冷冻干燥枣粉品质最佳，其次是真空干燥枣粉和变温压差膨化干燥枣粉，热风干燥枣粉品质最差。真空冷冻干燥和真空干燥生产成本高，变温压差膨化干燥枣粉品质较好，且所需干燥时间短，生产效率高、成本低，适宜在枣粉加工产业推广。

Effect of Drying Methods on Quality Characteristics of Jujube Powder

The physical properties and nutritional contents of jujube powder prepared by explosion puffing drying, vacuum
drying, hot air drying and vacuum freeze drying were measured and analyzed to explore the effects of drying methods on
quality characteristics of jujube powder. The results showed that the color of jujube powder prepared by vacuum drying and
vacuum freeze drying were much better; jujube powder prepared by vacuum freeze drying was less soluble than that obtained
from the other methods; no significant difference was found in hygroscopicity; jujube powder prepared by explosion puffing
drying and hot air drying had better rehydration, while jujube powder prepared by vacuum freeze drying had the smallest
particle size and bulk density. The nutritional contents of all four kinds of jujube powder were decreased compared with
fresh winter jujube, but reducing sugar and total sugar content of jujube powder prepared by explosion puffing drying and
vacuum freeze drying were higher; jujube powder prepared by vacuum drying had the highest level of total acid content;
vitamin C and flavonoid contents of jujube powder prepared by vacuum drying and vacuum freeze drying were higher;
Cyclic adenosine monophosphate contents in jujube powder prepared by vacuum freeze drying and explosion puffing drying
were higher than in that obtained from the other two methods. Based on the results of comprehensive scoring, the quality of
jujube powder prepared by vacuum freeze drying was the best, followed by vacuum drying and explosion puffing drying,
while jujube powder prepared by hot-air drying was the worst. However, high cost was needed for vacuum freeze drying
and vacuum drying. In conclusion, jujube powder prepared by explosion puffing drying has better overall quality with high
drying efficiency and low cost, which makes it suitable for extensive application in jujube powder processing industry.