烤煙變黃期葉綠素降解動力學分析

　　摘要：為研究不同烤煙品種的變黃特性和預測變黃期煙葉葉綠素含量變化，通過分析不同品種（紅花大金元、K326和云煙85）在不同變黃溫度（34 ℃、36 ℃、38 ℃、40 ℃和42 ℃）下煙葉葉綠素含量變化，建立了煙葉葉綠素降解動力學模型。試驗結果表明：（1）隨著變黃溫度的升高煙葉葉綠素降解加快，變黃溫度較低時（34 ℃、36 ℃）煙葉葉綠素降解存在延滯期，高溫變黃（40 ℃、42 ℃）不存在延滯期；相同變黃溫度下，云煙85煙葉葉綠素降解最快，K326次之，紅花大金元最慢。（2）利用一階反應模型可以很好地描述變黃期煙葉葉綠素含量變化，隨著變黃溫度升高煙葉葉綠素降解半衰期t1/2縮短，紅花大金元、K326和云煙85煙葉葉綠素降解活化能分別為61.76、56.20和53.16 kJ/mol；（3）試驗建立了基于溫度波動變化的葉綠素降解反應模型，為預測實際變黃過程中煙葉葉綠素含量變化提供理論參考。
　　關鍵詞：烤煙；變黃期；葉綠素；降解動力學；模型
　　中圖分類號：TS44+1文章編號：1007-5119（2017）04-0086-06DOI：10.13496/j.issn.1007-5119.2017.04.014
　　Abstract： In order to study the yellowing characteristics ofdifferent tobacco varieties and predict the changes of chlorophyll content during the yellowing stage. Changes of flue-cured tobacco leaves’ chlorophyll content in different varieties （Honghuadajinyuan， K326， Yunyan85） under different yellowing temperature （34 ℃， 36 ℃， 38 ℃， 40 ℃and 42 ℃） were analyzed， and the degradation kinetic model of flue-cured tobacco leaves’ chlorophyll was established. The results showed that flue-cured tobacco leaves’ chlorophyll content got a faster degradation with the increase of yellowing temperature. There was a lag phase of flue-cured tobacco leaves’ chlorophyll degradation at the low yellowing temperature （such as 34 ℃ and 36 ℃）， however， there was no lag phase at the high yellowing temperature （such as 40 ℃ and 42 ℃）. The chlorophyll degradation of the Yunyan-85 variety was the fastest， followed by the variety of K326， and the variety of Honghuadajinyuan got the slowest degradation. The first-order reaction kinetic model can well describe the variation of flue-cured tobacco leaves’ chlorophyll content during the yellowing stage.The half-life（t1/2）of flue-cured tobacco leaves’ chlorophyll degradation was shortened with yellowing temperature increased. The chlorophyll degradation activation energy of the varieties of Honghuadajinyuan， K326 and Yunyan85 leaf were 61.76， 56.20 and 53.16 kJ/mol respectively. The chlorophyll degradation reaction model based on the variation of temperature fluctuation was established in the test， which could provide a theoretical reference for the accurate prediction of the changes of chlorophyll content in tobacco leaves during the yellowing stage.
　　Keywords：flue-cured tobacco； yellowing stage； chlorophyll； degradation kinetics； model
　　變黃是煙葉烘烤過程的主要任務之一，煙葉變黃主要與葉綠素的降解有關[1]。通常烘烤過程中煙葉葉綠素不斷被降解、含量逐漸減少，類胡蘿卜素雖然也發(fā)生降解，但其降解較慢、降解量小，致使類胡蘿卜素等黃色素比例增加，煙葉逐漸呈現(xiàn)黃色[1-2]。葉綠素含量也是衡量烤后煙葉品質的主要指標[3-4]，葉綠素含量較高時，烤后煙葉外觀等級較差，評吸時青雜氣明顯。變黃期是煙葉色素降解的關鍵時期，煙葉有80%以上的葉綠素被降解[1]，因此研究變黃期煙葉葉綠素的降解特性具有重要意義。

相關熱詞搜索：葉綠素 烤煙 降解 動力學 變黃