气体射流冲击干燥对紫甘薯色泽及抗氧化性的影响

为了提高紫薯干制品质,研究不同风温、风速、预处理、气体喷嘴距物料盒高度及物料切片厚度对气体射流冲击干燥紫薯色泽、总花青素、多酚氧化酶(PPO)活性、总酚及总酚抗氧化能力的影响。结果表明,总花青素含量、总酚含量、抗氧化能力和PPO活力在干燥前后均有显著的降低。且色差值、总花青素含量、总酚含量及抗氧化能力随微波处理时间、喷嘴高度和切片厚度的增加而增加,随风温和风速的增加而降低。PPO活力随预处理时间和风温的增加而降低,但风速、喷嘴高度和切片厚度对PPO活力影响不显著。干燥前期(0~1 h)是有效控制紫薯干燥品质的最佳时间段。

Effects of Drying Purple Sweet Potato with Air-impingement Jet on Color and Antioxidative Components

In order to improve the purple sweet potato (PSP) drying quality, the effects of air-impingement jet drying PSP on colour, total anthocyanin contents, total phenolic contents, polyphenoloxidase activity and antioxidant activity in different pretreatment, nozzle distance, slice thickness, air temperature and air velocity were studied. The results shown that, there are significant reducing in total anthocyanin contents, total phenolic contents, antioxidant activity and polyphenoloxidase activity from fresh samples to dried samples. In addition, the ?E, total anthocyanin contents, total phenolic contents and antioxidant activity increased with the increasing of microwave pretreatment times, nozzle distance and slice thickness, decreased with the increasing of air temperature and air velocity. Polyphenoloxidase activity decreased with microwave pretreatment times and air temperature increasing. But there are no significant differences in polyphenoloxidase activity among four levels respectively in the factors of air velocity, nozzle distance and slice thickness. The best quality control times of PSP drying is in the initial period of air-impingement jet drying (0~1h).