胡萝卜吸附式低温干燥特性的研究

Research of drying characteristics on the low-temperature adsorption drying of carrot

对胡萝卜吸附式低温干燥过程的干燥特性进行了试验研究。考察了干燥气体 (空气 )的湿度和风量以及物料粒度对胡萝卜干燥特性和复水比的影响 ,得到形状相似的干燥曲线 ,用自定义最小二乘法拟合均能获得较好的结果。结果表明 :吸附式低温干燥过程可使被干燥物料达到超干水平 (含水率 <5 % ) ;增加干燥气体流量对干燥过程进行有利 ,当气体流量从 2 0 0L/h增加到 4 0 0L/h时 ,胡萝卜含水率从 4 1 13%降低到 34 93% ;被干燥物料颗粒大小和形状对干燥过程有显著影响 ;经过吸附式干燥后的胡萝卜色泽鲜艳 ,无褐变 ,外表品质优于热风干燥。吸附式低温干燥后胡萝卜的复水比 (6 5 2 )显著高于热风干燥 (1 78)。

The drying characteristic of carrot was studied exp er imentally using the low-temperature adsorptive drying system The effect of th e humidity, flow rate of dried-air and granularity of raw material on the dryin g characteristics and rehydration rate were investigated The drying curves had a nalogous shape and the results of nonlinear estimation models with custom least square approximation method suited specially The results show that: Raw materi a l can be over-drying (moisture content is under 5%) Adding the flow rate of d r ied-air can accelerate drying process When the flow rate of dried-air was in c reased from 200 L/h to 400 L/h, the moisture content was decreased from 4113% t o 3493% The granularity and shape have the important effect on drying proces s The carrot can keep basically original color and shows no browning, good surfa c e and high qualities versus the hot air drying The rehydration rate of the low -temperature adsorptivedrying (652) is visibly higher than that of the hot ai r drying (178)