百合热风薄层干燥特性及干燥品质

为提高规模化生产的百合品质,缩短干燥周期,以兰州百合为试样,运用JK-LB1700型薄层干燥试验台制干。系统研究了不同热风温度(60,70,80,90℃),热风速度(0.5,1.0,1.5,2.0m/s)和湿度(20%,30%,40%)对百合热风薄层干燥速率、色泽ΔE*值、VC含量、复水比的影响及各指标的变化规律;通过Weibull分布函数模拟了百合干燥过程及水分扩散规律。结果表明:随热风温度、热风速度增大百合热风薄层干燥时间显著缩短(P<0.01),不同相对湿度下无差异,但在干燥前期湿度大小与物料干燥速率呈正相关,后期呈负相关。采用Weibull分布函数能够准确(R2>0.99)描述百合热风薄层干燥过程,基于Weibull分布函数可准确获得百合薄层干燥水分有效扩散系数(1.213×10-6~3.992×10-6 m2/s),Deff值不仅受干燥参数影响,也受干燥设备和试样贮存时间的影响。试验干燥参数对百合品质指标色泽ΔE*值、VC含量和复水比的综合影响大小依次为干燥温度>热风速度>相对湿度,品质指标色泽ΔE*值和VC含量受干燥参数影响较大,复水比较小。

Drying characteristics and drying quality of Lilium by hot-air thin-layer drying

In order to improve the quality of lily production and shorten the drying period,taken Lanzhou lily as sample and used JK-LB1700 thin layer drying test bed to dry.The effects were investigoted,in different hot-air temperature(60,70,80,90 ℃),hot-air rate(0.5,1.0,1.5,2.0 m/s)and drying relative humidity(20%,30%,40%)on drying rate,colorΔE*value,vitamin C content,rehydration ratio during lily drying and law of change.The Weibull distribution function was used to simulate the drying moisture diffusion law of lily.Results,the drying time of lily was significantly shortened(P<0.01)with the hot air temperature and hot air speed increasing.There was no difference under different drying relative humidity,but the humidity was positively correlated with the drying rate of the lily in the early drying stage,and negatively correlated in the later stage.Weibull distribution function can accurately(R2>0.99)describe drying process,and basing on Weibull distribution function,effective water diffusion coefficient was obtained between 1.213×10-6~3.992×10-6 m2/s.Deffvalues were not only affected by drying parameters,but also by drying equipment and sample storage time.The combined effects order of experimental drying parameters on the colorΔE*value,vitamin C content and rehydration ratio were dry temperature>hot air speed>relative humidity,and the quality index colorΔE*value and vitamin C content were greatly affected by drying parameters,rehydration was relatively small.