干燥方式对黑塌菜粉品质的影响

目的:以如皋市特产富硒黑塌菜为原料，研究冰温真空干燥对黑塌菜粉品质的影响。方法:将新鲜黑塌菜预处理后，冰温真空干燥至含水率(5.0±0.5)%,并以热风干燥、真空干燥和冷冻真空干燥为对照组，考察其理化指标。结果:冰温真空干燥维生素C含量为554.60 mg/100 g,保留率达83.96%,较热风干燥、真空干燥和冷冻真空干燥分别提高了43.11%,33.57%,1.61%;谷胱甘肽过氧化物酶酶活损失较小，纯度维持最好；总酚和总黄酮保留率分别为59.69%和60.58%,整体优于其他3组；微观结构方面，冰温真空干燥组菜粉粉末分布均匀，表面光滑平整、碎屑少；相较其他3组，冰温真空干燥组菜粉能够保持原有深绿色泽，复水性和溶解度相较于热风干燥和真空干燥有所提高。结论:冰温真空干燥对黑塌菜粉品质影响最小，营养品质最高。

Effect of different drying methods on the quality of Rugao black pakchoi

Objective: This study aimed to investigated the effect of ice-temperature vacuum drying on the powder quality of selenium-rich Rugao black pakchoi. Methods: After pretreatment, the fresh black pakchoi was dried to the moisture content of (5.0±0.5) %, and the physical and chemical indexes were investigated, comparing to the control groups of hot-air drying, vacuum drying and freeze-vacuum drying. Results: The vitamin C content of vacuum drying at ice temperature was 554.60 mg/100 g, and the retention rate reached 83.96%, which was 43.11%, 33.57% and 1.61% higher than that of hot-air drying, vacuum drying and freeze-vacuum drying, respectively. Glutathione peroxidase had little activity loss and the best purity maintenance. The retention rates of total phenols and total flavonoids were 59.69% and 60.58%, respectively, which were better than the other three groups. In terms of microstructure, the powder of ice-temperature vacuum drying group was well-distributed, with a smooth and flat surface and less debris. Compared with the other three groups, the ice-temperature vacuum drying group could maintain the original dark green color, and the rehydration and solubility were improved. Conclusion: The ice-temperature vacuum drying process can minimally affect the Rugao black pakchoi powder, and the nutritional quality of this powder is the highest.