Effects of Different Flue-curing Barns on Aroma Quality of Upper Flue-cured Tobacco Leaves of K326

[Objective] This study was conducted to compare the aroma quality of up-per leaves of K326 flue-cured in different barns, and provide theoretical references for the development and optimization of bulk curing barn and the supporting tech-niques. [Method] The upper leaves of K326 were flue-cured in a commonness barn, a four-shelf bulk curing barn and a three-shelf bulk curing barn separately, and then the contents of aroma components and taste quality indices of the finished leaves were measured and compared. [Result] The contents of total aroma components, chromoplast pigment degradation products, phenylalanine aroma components and neophytadiene showed no significant differences in the leaves flue-cured in four-shelf bulk curing barn and commonness barn, but were significantly or very significantly higher than those in the leaves flue-cured in three-shelf bulk curing barn. The con-tents of carotenoid degradation products, Mail ard reaction products, cembranes aro-ma components and total aroma components （except neophytadiene） showed no significant difference among the three treatments. The results of sensory evaluation revealed that the sensory taste of the leaves flue-cured in four-shelf bulk curing barn was the best, as the finished leaves had rich, delicate aroma, comfortable and clean aftertaste. The leaves flue-cured in commonness barn was better than those flue-cured in three-shelf bulk curing barn in aroma quality, amount and aftertaste. [Conclusion] The four-shelf bulk curing barn had a large volume for tobacco leaf processing, but a similar baking environment to the commonness barn, which is conducive to the formation and accumulation of aroma components, so the finished leaves had similar appearance and quality with those flue-cured in commonness barn. The upper flue-cured leaves in three-shelf bulk curing bran had poorer quality than those flue-cured in the other two barns.

Present Situation and Prospect of Professional Grading and Loose-leaf Purchasing of Flue-cured Tobacco

In terms of the common practice of professional grading and loose-leaf purchasing technology, the advantages of these technologies were demonstrated. The problems and proposals of the professional grading leaves purchasing model were also summarized and analyzed, so as to provide practical experiences for fur- ther promotion of loose-leaf purchasing.

Studies on Amylase and Degradation of Starch and Pigment of Tobacco Leaf During Process of Flue-Curing

The changes in the activity of amylase and amylase-isoenzyme and the degradation of starch and pigment of tobacco leaf during flue-curing were studied by using the electric- heated flue-curing barn designed and made by the Henan Agricultural University. The temperature and humidity of the barn were controlled automatically. The results indicated that starch in tobacco leaf decreased rapidly and leveled off after 48 h of curring, in the meantime, the content of soluble sugar increased accordingly and reached a peak at the stage of color-fixing. Both of them had a rapid-changing stage in the first 36 hours of yellowing. The changes of starch and soluble sugar contents had highly significant negative-correlation at 1 % level (rNC89 = -0.8962**, rYY85 = -0.9704**). The activity of amylase increased with the proceeding of curing and reached a peak after 36 hours of curing, then decreased. But the activity of amylase kept at a high level when the humidity of curing-environment was very low, even if the tobacco leaf had been dried. The rapid degradation of starch showed a significantly negative correlation with the increase of activity of amylase at 5 % level (rNC89 = -0.8495*, rYY85 = -0.7839*). The degradation of starch and pigment had the same regulation and had highly significant correlation at 1 % level (rNC89= 0.9649**, rYY85= 0.9428**). There were mainly three amylase-isoenzyme bands -A, B, C respectively, in tobacco leaf during flue curing. They were identified as α-AMY, β-AMY, R-AMY, and the activity of β-AMY was the highest. The changes in amylase activity and contents of starch and pigment were affected by the tobacco leaf moisture and environmental humidity during curing.

Problems and Countermeasures of Acquisition of Professionally-graded Flue-cured Tobacco Loose Leaf

Based on existing problems of loose leaf acquisition,some measures can be taken,including improvement of acquisition infrastructure,innovation of acquisition and management models,reinforcement of professional services and training,high-lighting grading management,which would not only reduce farmers＇ efforts,but also lower storage pressure,as well as improving grading quality of tobacco leaf.

Effect of Different Flue-curing Techniques on the Taste and Aroma Substances of Tobacco Leaves

[Objective]This study aimed to optimize the conditions for curing tobacco leaf, so as to improve its flavor and quality. [Method] Leaves of Yuanyan 87 were col ected and cured by three different techniques （moderate-intensity conditions throughout the curing course; high-intensity conditions at leaf yel owing and wilting stages, moderate-intensity conditions at leaf drying and vein drying stages; high-in-tensity conditions throughout the curing course）, and then the contents of 48 aroma substances and taste indices of the finished tobacco leaves were measured. [Result] The contents of 28 aroma substances in the tobacco leaves cured under high-inten-sity conditions throughout the course were higher and the taste indices of these to-bacco leaves were better, compared with those flue-cured by the other two tech-niques. The contents of the other 20 aroma substances were not significantly af-fected by the curing techniques. The second best technique was high-intensity con-ditions at leaf yel owing and wilting stages and moderate-intensity conditions at leaf drying and vein drying stages. Curing tobacco leaves at moderate-intensity condi-tions throughout the course was the worst one. [Conclusion] Compared with the oth-er two methods, the contents of aroma substances and taste indices of the tobacco leaves cured under high-intensive conditions throughout the course were the best.

Analysis of Growth Laws of Leaves of Flue-cured Tobacco in Various Periods

The growth laws of leaves of flue-cured tobacco in different positions in various periods were summarized. The results showed that the growth speed of new leaves of flue-cured tobacco increased constantly until their growth was the fastest, and then it reduced irreversibly. The length and width of leaves in each position increased fastest when they grew depending on photosynthates instead of or- ganic compounds from functional leaves. Therefore, it is concluded that the increases of leaf length, width and area, and dry matter, and the peak of photosynthetic rate appear successively during the process of leaves of flue-cured tobacco, and the leaf area correction coefficient of leaves of flue-cured tobacco is related to the shape of leaves, which are affected by leaf position and the variety of flue-cured tobacco. The study can provide scientific reference for further research on the growth laws of leaves of flue-cured tobacco.

Dynamics of Environmental Humidity and Water Content in Tobacco Leaf and Metabolism of Starch During Curing

Effect of environmental humidity and water content in tobacco leaf on starch metabolism was studied by using the electric-heated auto-controlled flue-curing barn supplied by Henan Agricultural University, China. The results indicated that the degradation of starch and decrease of water content in tobacco leaf during early yellowing at low humidity was the most rapid, and the water loss was the highest while the lowest under high humidity. The duration for starch degradation under low humidity was longer than that of CK. So the starch residue in cured leaf of different treatment took the order of high humidity yellowing treatment> low humidity yellowing treatment > CK. When the leaf water content was decreased to around 50 %, the starch degradation became slow and the content of starch was stable. Starch degradation and decrease of leaf water content was not synchronous. Starch in tobacco leaf during yellowing degraded more rapidly when humidity was decreased at a high speed, but the degradation stopped earlier at late stage. There was a quicker and higher degradation of starch under high environmental humidity. When the humidity decreased to 70 %, the content of starch was stable. The activity of amylase began to decrease when relative humidity was below 75 %, but it kept a high level of activity when the environmental humidity was below 70 %.

Effects of Curing Techniques on Starch Contents of Leaves in Different Tobacco Parts with Varying Maturity Degrees

[Objective] The aim was to explore effects of different curing techniques on starch contents of tobaccos from different growth parts and with varying maturity degrees in order to reduce starch content of Yunnan tobacco. [Method] Compar- isons were conducted on tobaccos from upper, middle and down parts （immature, premature, mature and excessive mature） by low temperature and low humidity cur- ing technique, moderate temperature and moderate humidity curing technique, mod- erate temperature and high humidity curing technique to measure starch contents before and after curing. [Result] The results showed starch content of tobacco was increasing upon growth part. Low temperature and low humidity curing technique has poor effects on reduction of starch content; moderate temperature and moderate humidity curing technique improves starch content; moderate temperature and high humidity curing technique dramatically reduces starch content of tobaccos. [Conclu- sion] With consideration of tobacco appearance, inner quality and characters, moder- ate temperature and moderate humidity curing technique is recommended for tobac- co production.

Correlations between Quality Index and Content of Cellulose and Lignin in Upper Leaves of Fluecured Tobacco in Wulin Mountain Area

In order to study the correlations among quality indexes of tobacco leaf and contents of cellulose and lignin in upper leaves of flue-cured tobacco, 48 B2F flue-cured tobacco samples in seven counties of Wulin mountain area in 2011 and 2012 were used as test materials to measure the contents of cellulose and lignin in tobacco leaves and analyze the differences among varieties and between years. Meanwhile, correlations among contents of cellulose and lignin and appearance quality, physical characteristics, general chemical components and indexes of senso- ry quality were studied. The results showed that the contents of cellulose and lignin had no significant difference among years and varieties. Cellulose content was sig- nificantly correlated with some indexes of appearance qualities, physical indexes, general chemical compositions and sensory qualities. Lignin content was significantly correlated with grayness and oil content but not other quality indexes of tobacco leaf. It could be seen that the differences of cellulose and lignin contents between different years and among varieties were not significant. Cellulose content was closely correlated with quality indexes of tobacco leaf while lignin content had a small effect on tobacco leaf quality.

Effects of the Combined Use of Tobacco Special Inorganic Fertilizer and Cake Organic Fertilizer on the Quality of Tobacco K326

[Objective] This study aimed to investigate the effects of the combined use of cake organic fertilizer and tobacco special fertilizer on the growth and development as well as the quality of tobacco leaves.[Method] Different ratios of cake organic fertilizer and tobacco special fertilizer were applied.Then,the agronomic traits and leaf quality determining factors were measured and analyzed at different growing stages.[Result] Compared with the control,the tobacco plant height was increased by 3.01％-5.84％,while the number of valid leaves was increased by 5.56％-20.39％ in all the treatments with combined use of fertilizers.The ratio of sugar to nicotine of leaf was closer to 10±1,and the ratio of nitrogen to nicotine of leaf was closer to 1±0.1.In addition,the combined use of 750 kg/hm2 tobacco special base fertilizer and 292 kg/hm2 cake organic fertilizer had a better effect for improving the agronomic traits and flavor qualities than all the other treatments.[Conclusion] This study will provide reference for developing special full-aroma tobacco leaf product and new tobacco special fertilizers in Hunan.

Climatic Characteristics of Hubei Tobacco Area and Its Influence on the Quality of Upper Leaves

In order to provide a more suitable environment for tobacco leaf growth, this study collected meteorological information and tobacco leaf quality information from the main tobacco-producing counties in the province and conducted relevant analysis to find out the main meteorological factors affecting the growth, development, yield, and quality of upper tobacco leaves. Clarify the suitable climatic conditions for the growth and development of the upper leaves, and clarify the influence of various meteorological factors on the quality of the upper leaves. The results showed that the nicotine and total nitrogen content of the upper leaves were significantly positively correlated with the average daily temperature during the maturity period, and negatively correlated with the rainfall during the maturity period;the rainfall in July was significantly positively correlated with the upper leaf clutter score, which was sufficient in the mature period. Moisture conditions are conducive to alleviating the upper leaf clutter;the number of sunshine hours in August is the main factor affecting the content of aroma substances in the upper leaves, and it is also significantly positively correlated with the content of aroma substances.

烟叶烘烤过程中叶片组织结构变化的研究

利用树脂包埋、半薄切片法对烘烤调制过程中烟叶组织结构的连续变化作了一定的研究，结果如下：（1）随着烘烤过程的进行，烟叶的栅栏组织、海绵组织逐渐收缩变薄，而上下表皮厚度变化细微，维管束的结构变化较为迟缓。（2）至干筋初期，栅栏组织、海绵组织和上下表皮的细胞均已破裂瓦解，内部结构混为一体。细脉中的维管束也开始破裂溶解，支脉和主脉的维管束结构还基本保持完整状态。