In order to explore the effects of drying temperature,loading density and wind speed on the drying characteristics and color of'Thompson Seedless'grapes,the changes in berry weight,raisin water content,color difference,and total phenol,chlorophyll,total sugar,total acid content and other quality indexes during the drying process were investigated,and the drying rate,greening rate and drying time were calculated to analyze the effects of different treatments on processing efficiency and raisin quality.The results showed that drying time was positively correlated with material temperature and wind speed,and negatively correlated with the loading capacity.There was no correlation between the content of total sugar in raisins and the drying process of grape fruits.'Thompson Seedless'grapes would browning significantly when the material temperature was 40℃;and the browning phenomenon was gradually aggravated when the loading amount was more than 15.62 kg·m-3 and the wind speed was more than 2 m·s-1.In conclusion,when the material temperature was 35℃,the wind speed was 1.0 m·s-1,and the loading quantity was 7.81 kg·m-3,the drying time of'Thompson Seedless'grapes was 148 h,and the content of chlorophyll and total phenol was 0.55 mg·g-1 and 0.15 mg·g-1,and color difference with raw materials was 6.99,and the rate of green products reached 64%.Raisins showed full grain,good color.
关键词
无核白/热风干燥/干燥特性/绿品率/色泽
Key words
Thompson Seedless/hot air drying/drying characteristics/green product rate/color
万方数据