[关键词]
[摘要]
本实验研究了不同对流干燥温度(60、70和80 ℃)和红外功率(675、1350和2025 W)对桑椹对流-红外联合干燥特性和干燥产品品质的影响。结果表明:干燥温度对干燥速率影响较红外功率大;干燥过程属降速干燥,由费克第二定律求出桑椹有效水分扩散系数在2.67×10-9~8.41×10-9 m2/s范围内,并随对流干燥温度和红外功率的增大而增大;由阿伦尼乌斯公式计算出桑椹干燥活化能为53.99 kJ/mol;干燥实验数据拟合结果显示,桑椹的对流-红外联合干燥过程符合Page模型;且在对流温度70 ℃,红外功率675 W干燥条件下物料品质最优。相比热风干燥与真空冷冻干燥,对流-红外联合干燥大大缩短了干燥时间,具有最高的总酚含量(30.33 mg/g)和较高的花色苷含量(11.55 mg/g),提高了产品的营养品质。该研究为对流-红外联合干燥技术应用于桑椹干燥提供了理论依据。
[Key word]
[Abstract]
The effects of convective-infrared radiation on the product quality of dried mulberries at different connective drying temperatures (60, 70 and 80 ℃) and infrared powers (675, 1350 and 2025 W) were investigated. The result showed that the connective drying temperature had a more significant impact on the drying rate. The drying process was a falling rate drying. The effective moisture diffusion coefficient of mulberries ranged from 2.67×10-9 m2/s to 8.41×10-9 m2/s according to Fick's Second Law, and it increased with increasing temperature and power. The drying activation energy of mulberry was 53.99 kJ/mol according to the Arrhenius equation. The experimental data regarding the combined convective-infrared radiation drying process of mulberries was fit according to the Page model. The best product quality was obtained under the conditions of 70 ℃ and 675 W. As compared with hot air drying and freeze drying, the convective-infrared radiation combination significantly shortened the drying time and improved the product quality, as indicated by the greatest total phenol content (30.33 mg/g) and greater anthocyanin content (11.55 mg/g). This study could serve as a theoretical foundation for convective-infrared radiation drying of mulberries.
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[基金项目]
公益性行业(农业)科研专项经费资助(201303073);新疆生产建设兵团科技支疆计划(2013AB020)资助