苹果渣过热蒸汽-热风联合干燥及干粉品质分析  

Apple pomace drying by superheated steam combined with hot air and the properties of dried powder

作　　者：黄小丽[1] 肖旭霖[1] 许伟[1] 谢星[1] 郭玉蓉[1] 

机构地区：[1]陕西师范大学食品工程与营养科学学院,陕西西安710119

出　　处：《食品与发酵工业》2017年第7期194-200,共7页Food and Fermentation Industries

基　　金：陕西师范大学中央高校基本科研业务费专项(GK201503072)和创新团队专项(GK201601007)

摘　　要：果渣传统干燥存在干燥时间长、能耗大、果渣褐变严重等问题。尝试采用联合干燥方法对苹果渣进行脱水:前段(果渣含水率81%~63%)采用过热蒸汽干燥,后段(果渣含水率63%~7%)采用热风干燥。为了研究苹果渣过热蒸汽干燥特性,选取蒸汽温度和流速为试验因素,设计了2因素4水平全面正交试验;苹果渣热风干燥条件固定:70℃、1.5 m/s。结果表明,苹果渣过热蒸汽干燥存在预热冷凝和恒速干燥段;苹果渣过热蒸汽干燥速率随蒸汽温度上升而加快,蒸汽流速对干燥速率的影响不显著;经过热蒸汽干燥后,苹果渣热风干燥时间显著减少;联合干燥所得苹果渣干粉色度值a和b较小,颜色较浅,苹果渣干粉持水力和吸油力范围分别为4.82~7.77和0.83~1.32,平均果胶提取得率9.3%;与单一热风干燥相比,采用过热蒸汽联合热风干燥苹果渣可大大减少干燥时间,且干燥所得苹果渣干粉褐变得到了较好地抑制,果胶提取率较高。There are a series problems for conventional apple pomace drying , such as, long drying time, high energy consumption, severe browning. Combined drying method was used in this study. Superheated steam drying was used first when moisture content from 81% to 63% , and then hot air drying was applied to continue reduce the mois- ture content from about 63% to 7%. In order to study the superheated steam drying characteristics of apple pomace, two- factor, four-level orthogonal experimental scheme was designed using steam temperature and velocity. The hot air drying condition was set at 70℃ , 1.5m/s. Results showed that the drying process had condensation and constant dr- ying periods, and the dehydration rate of apple pomace was increased with the increase of steam temperature. The ve- locity of superheated steam had little effect on the drying. With superheated steam, the hot air drying time was short- ened remarkably. The color values a and b of the apple pomace powder dried with combined drying method were low- er, which means the browning of dried apple pomace powder was getting better. The water holding capacity, oil hold- ing capacity and average pectin yield ratio of dried apple pomace powder were 4.82 to 7.77, 0.83 to 1.32 and 9.3% , respectively. Compared to single hot air drying, superheated steam combined with hot air drying can success- fully reduce the drying time and the browning of apple pomace, and increase pectin yield ratio. These results can be used as a guide in reuse of apple pomace.

关 键 词：过热蒸汽干燥 苹果渣 干燥特性 干燥速率 果胶提取得率 

分 类 号：TS209[轻工技术与工程—食品科学]