【作者】 黄永成；

【导师】 宫长荣；

【作者基本信息】 河南农业大学 ， 烟草学， 2008， 硕士

【摘要】 不同烘烤工艺条件下烤后烟叶香气质量有很大差异,因此,研究不同烘烤调控措施对烟叶香气的影响具有重要的意义。2006—2007年采用河南农业大学设计的电热式温湿自控密集烤烟箱,研究了烘烤变黄温湿度和定色升温速度对烟叶一些生理生化特性和香气质量的影响,主要结论如下:1.在烘烤过程中,烟叶在0-24h失水速度慢,平均失水速度为0.16%/h;24-72h失水速度快,平均失水速度为0.99%/h;高温变黄条件比低温变黄条件下失水速度快,在相同温度条件下,烟叶的失水速度表现为低湿(相对湿度75-70%)>中湿(相对湿度85-80%)>高湿(相对湿度95-90%)。2.不同温湿度处理下POD活性呈下降趋势,以低温中湿变黄和高温中湿变黄下,POD活性相对较高;不同变黄温湿度处理下,PPO活性均呈现“升高-降低-升高-降低”的趋势,低温低湿,低温中湿,高温低湿三个处理下PPO活性较低,其余处理PPO活性较高。3.不同变黄温湿度处理下PAL活性呈现出相同的变化趋势。烘烤前期(0-36h)降低,烘烤36h后酶活性升高,到60h时达到顶点,以后又开始降低。并且烘烤前期,高温处理酶活性相对较高,烘烤后期相对较低。低温处理下情况正好相反。在烘烤72h内,低温低湿和低温中湿变黄处理下PAL活性相对较高。4.不同变黄温湿度处理下0-36h内,各处理LOX活性一直上升,其中,低温低湿、高温低湿和高温中湿处理脂氧合酶活性在烘烤后36h达到峰值,随后下降,低温中湿、低温高湿和高温高湿和处理在烘烤后48h时达到高峰,随后降低。在烘烤72h内,低温中湿、低温高湿和高温高湿和处理下脂氧合酶活性相对较高。5.叶绿素降解规律均为:在前12h内比较慢,以后明显加快,烘烤36h后叶绿素降解速度开始减慢,48h后趋于平缓。其中低温低湿、低温中湿和高温低湿处理下叶绿素降解量较大,高温高湿、低温高湿和高温中湿处理下叶绿素降解量相对较少。β-胡萝卜素在不同变黄温湿度处理下变化动态基本一致,在0-12h内略有减少,随后急剧减少,烘烤48h后趋于稳定。变黄阶段六个处理β-胡萝卜素降解量为:低温中湿(80.25%)>低温低湿(78.49%)>高温中湿(71.29%)>高温高湿(70.08%)>低温高湿(69.84%)>高温低湿(66.41%)。叶黄素、新黄质和紫黄质在不同变黄温湿度处理下变化趋势一致,0-24h内,降解缓慢,随后急剧降解,48h后趋于稳定。变黄阶段在低温低湿下这三种色素降解量为最大,其次为低温中湿。6.不同变黄温湿度烤后烟叶中色素含量差异很大。低温中湿变黄处理下β-胡萝卜素含量最低,为56.0604μg/g,仅为高温中湿变黄处理的1/2,其它处理间差别不明显。叶黄素、新黄质和紫黄质含量以低温低湿和低温中湿下含量较低。7.不同变黄处理烤后烟叶中性香气成分含量,低温中湿(2143.43μg/g)>低温低湿(1896.91μg/g)>低温高湿(1661.75μg/g)>高温低湿(1645.09μg/g)>高温高湿(1534.30μg/g)>高温中湿(1373.2μg/g)。在低温中湿变黄条件下烤后烟叶物理性状较好,烟碱、总氮、淀粉、硝酸盐和亚硝酸盐含量含量较低;总糖、还原糖、钾、游离氨基酸、石油醚提取物、总酚、绿原酸和芸香苷含量含量含量较高;糖碱比相对较高(8.66)。8.与快速升温定色处理相比,慢速升温定色下POD、PPO、PAL和LOX活性较高,β-胡萝卜素、叶黄素、新黄质和紫黄质降解量相对较多。9.慢速升温定色处理烤后烟叶中β-胡萝卜素、叶黄素、新黄质和紫黄质含量较少,烟叶色素降解较为充分。10.在慢速升温定色处理下,烤后烟叶中除梅拉德反应产物类和快速升温定色处理差别不大外,芳香族氨基酸代谢产物、类胡萝卜素降解产物、西柏烷类降解产物、新植二烯类含量明显高于快速升温定色处理。慢速升温定色处理烤后烟叶颜色、油分、色度较好,烟碱、总氮、淀粉含量比较低,总糖、还原糖、钾、硝酸盐、亚硝酸盐、石油醚提取物和游离氨基酸含量比较高。更多还原

【Abstract】 Aroma matter of flue—cured tobacco is accumulated in field,but it is displayed through curing and highly different in different curing treatment.so it has important meaning to study the influence of different curing treatment to aroma matter. This experiment studied the influence of different curing treatment to aroma matter and physiological and biochemical characteristics of tobacco with electric-heated flue-curing barn, The main results are as follows:1.During the flue-curing process,the water loss rate of tobacco leaf is slow in 0—24 hours.the average of water loss rate is 0.16% per hour, the water loss rate of tobacco leaf is quick in 24—72 hours.the average of water loss rate is 0.99% per hour,the water loss rate is faster in high temperature yellowing treatment than that in low temperature yellowing treatment.In the same temperature condition, the water loss rate was low humidity(relative humidity 75~70%)>middle humidity(relative humidity 85~80%)>high humidity(relative humidity 95~90%).2.The activitie of POD showed downtrend under different temperature and humidity treatments, the activities of POD was higher in low temperature middle humidity and high temperature middle humidity treatment. The activities of PPO showed“rise~reduce~rise~ reduce”in six temperature and humidity treatments,it was lower under low temperature low humidity, low temperature middle humidity and high temperature low humidity treatment.3.The activitie of PAL showed the same change trend under different temperature and humidity treatments, during the early stage of curing(0-36h), the activitie of PAL was descreased,during 36h to 60h the activitie of PAL was increased, reached its peak at 60h, then declined. Under high temperature treatment, the enzyme activities was higher in the early stage of curing and was lower in the later stage of curing.But it was contrary under low temperature treatment.During 72h the activitie of PAL was higher under low temperature low humidity and low temperature middle humidity treatment.4.The activitie of Lox was acended during 0-36h under different temperature and humidity treatments,it reached the peak at 36h under low temperature low humidity, high temperature low humidity and high temperature middle humidity treatment,then decreased. The activitie of Lox reached the peak at 48h under low temperature middle humidity treatment, low temperature high humidity treatment and high temperature high humidity treatment,then decreased. During 72h the activitie of Lox was higher under low temperature middle humidity, low temperature high humidity and high temperature high humidity treatment.5.Degradation rule of chlorophyll was”slow-fast-slow”. The chlorophyll declined rapidly under low temperature low humidity, low temperature middle humidity and high temperature middle humidity treatment.Theβ-carotene showed the same change trend under different temperature and humidity treatments,it had a little decrease during 0-12h,then reduced rapidly, tended to be stable ofter 48h. The degradation amount ofβ-carotene was:low temperature middle humidity(80.25%)>low temperature low humidity(78.49%)>high temperature middle humidity(71.29%)>high temperature high humidity(70.08%)>low temperature high humidity(69.84%)>high temperature low humidity(66.41%).The lutein, neoxanthin and violaxanthin showed the same change trend under different temperature and humidity treatments, it had a little decrease during 0-24h, then reduced rapidly, tended to be stable ofter 48h. The amount of the three colorant decomposed under low temperature low humidity treatment was the highest,then was under low temperature middle humidity treatment.6.There is great difference of colorant in cured tobacco leaf under different temperature and humidity treatments. The amount of theβ-carotene under low temperature middle humidity treatment was the lowest, is only half of that under high temperature middle humidity treatment, it showed no significant difference in other treatment. The amount of lutein, neoxanthin and violaxanthin was lower under low temperature low humidity and low temperature middle humidity treatment.7.the contents of neutral aroma components were different in cured tobacco leaf under different temperature and humidity treatments.low temperature middle humidity(2143.43μg/g)>low temperature low humidity(1896.91μg/g)>low temperature high humidity ( 1661.75μg/g ) > high temperature low humidity(1645.09μg/g)>high temperature high humidity(1534.30μg/g)>high temperature middle humidity(1373.2μg/g).The physical properties of cured tobacco leaf was best under low temperature and middle humidity yellowing condition, every index was within the range of the suitable one; The content of nicotine , total nitrogen and starch in tobacco leaf were reduced, The content of total sugar,reducing sugar,K were improved, the chemical composition was harmonized.8.Under the curing condition of tobacco leaves fixing-color at slow speed,the activitie of POD,PPO,PAL and LOX was higher,and the amount of theβ-carotene, lutein, neoxanthin and violaxanthin decomposed was higher.9.The amount of lutein, neoxanthin and violaxanthin was lower under the curing condition of tobacco leaves fixing-color at slow speed,the amount of the colorant decomposed fully the curing condition of tobacco leaves fixing-color at slow speed.10.The amount of Maillard reaction products in cured tobacco leaves had little difference under fixing-color treatment,but the amount of neoplytadiene,products degraded by carotenoid,products of aromatic amino acid metabolism,products degraded by cembrane in cured tobacco leaves was higher under the curing condition of tobacco leaves fixing-color at slow speed.The physical properties of cured tobacco leaf was better under the curing condition of tobacco leaves fixing-color at slow speed, every index was within the range of the suitable one; The content of nicotine , total nitrogen and starch in tobacco leaf were reduced, The content of total sugar,reducing sugar,K were improved, the chemical composition was harmonized.更多还原