基于Weibull函數(shù)的烤煙干筋期干燥動(dòng)力學(xué)及顏色分析

　　摘要：【目的】分析干筋期烤煙主脈干燥特性和顏色變化，為干筋期烤煙烘烤工藝優(yōu)化提供參考�！痉椒ā恳栽茻�87中部葉為試驗(yàn)材料，利用Weibull分布函數(shù)研究干筋期不同風(fēng)速（低速、中速和高速）、相對(duì)濕度（12%、18%和24%）和干球溫度（60、64、68和72 ℃）條件下煙葉主脈的干燥特性，并對(duì)烤后煙葉顏色參數(shù)值進(jìn)行分析�！窘Y(jié)果】干筋期煙葉主脈失水呈降速干燥，隨著干筋期風(fēng)速的增加、相對(duì)濕度的降低或干球溫度的升高，干燥速率加快。利用Weibull分布函數(shù)可很好地描述干筋期煙葉主脈水分干燥曲線，尺度參數(shù)α隨著風(fēng)速的增加、干球溫度的升高和相對(duì)濕度的降低而降低，形狀參數(shù)β受干筋條件影響較小�；�于Weibull分布函數(shù)的干筋期煙葉主脈估算水分?jǐn)U散系數(shù)Dcal在1.994×10-10～4.026×10-1 m2/s，干筋期煙葉主脈干燥活化能Ea為56.57 kJ/mol。隨著干筋期風(fēng)速增加，煙葉亮度L*和正反面亮度差?L*增大，顏色偏亮黃色；隨著干筋期相對(duì)濕度的增加，煙葉L*和正反面?L*減小，而紅度a*、黃度b*和飽和度C*逐漸增大，顏色偏橘黃色；隨著干筋期干球溫度的升高，煙葉a*增大，顏色偏紅棕色。【結(jié)論】烤煙干筋期采用較高的溫濕度和較低的風(fēng)速有利于提高干筋效率、增加煙葉飽和度。
　　關(guān)鍵詞： Weibull函數(shù)；干筋期；干燥特性；顏色值
　　中圖分類號(hào)：S572 文獻(xiàn)標(biāo)志碼：A 文章編號(hào)：2095-1191（2018）02-0333-07
　　Abstract：【Objective】In order to provide a theoretical reference for the optimization of curing process during stem drying stage， the changes of drying characteristics and color of tobacco midrib during stem drying stage was analyzed.【Method】In this study， the middle leaves of Yunyan 87 were used as experimental materials. Weibull distribution function was applied to analyze the drying characteristics of midrib during stem drying stage under different drying air velocities （low velocity， intermediate velocity and high velocity）， relative humidity（12%， 18% and 24%） and dry-bulb temperature（60， 64， 68 and 72 ℃），and the color parameters of flue-cured tobacco leaves were also studied. 【Result】The moisture dehydration of tobacco midrib was in a falling-rate drying process during stem drying stage， its drying rate was increased with the raise of air velocity， decrease of humidity or increase of dry bulb temperature. Weibull distribution function could well describe the drying curves of tobacco midrib during stem drying stage. It was found that the scale parameter α decreased as air velocity increased， humidity decreased and dry bulb temperature increased. And there was a lower influence on the shape parameter β under different stem drying conditions.The moisture diffusion coefficient Dcal of tobacco midrib during stem drying stage based on Weibull distribution was between 1.994×10-10 and 4.026×10-10 m2/s. The activation energy Ea for drying of tobacco midrib was 56.57 kJ/mol. The brightness value L*， the color difference between the front and back of leaves ?L* increased with the increase of air velocity， the color of tobacco leaves was bright yellow. The brightness value L* and the color difference between front and back of leaves ?L* decreased with the increase of relative humidity， while the redness value a*， yellowness value b* and color saturation C* increased gradually， the color of tobacco leaves was close to orange. In addition， the redness value a* increased with the raise of dry bulb temperature， the color of tobacco leaves was reddish brown. 【Conclusion】High temperature， high humidity and low air velocity during tobacco stem drying stage is benefit for improving the drying efficiency and increasing the color saturation of tobacco leaves.

相關(guān)熱詞搜索：烤煙 動(dòng)力學(xué) 函數(shù) 干燥 顏色