| In 2018,the author conducted field experiments in Wangcun tobacco production base in Luoning County,Luoyang City,Henan Province.Aiming at the imported cigar varieties,the author carried out cultivation measures such as different nitrogen levels,planting density and number of leaves left,recorded the impacts on the field agronomic characteristics and yield of tobacco plants,and evaluated and analyzed the physical characteristics,chemical composition and sensory quality of the fermented tobacco leaves.In addition,this paper also explored the change of the content of tobacco leaves in the fermentation process,and the control node of the optimal fermentation time.The results are as follows:1.Effect of different nitrogen levels on the quality of Luoning cigarThe quality of tobacco leaves was better when the nitrogen dosage was 8kg/667m2(N2).(1)The effect of nitrogen is mainly in the early growth stage.75 days after transplanting,there was no significan difference among the other treatment except N1.(2)With the increase of nitrogen application,the middle and upper leaves of each treatment were as follows:the weight of single leaf increased,the weight of leaf quality and the thickness of leaf decreased first and then increased,and the equilibrium moisture content decreased;the content of nicotine and total nitrogen increased,total sugar,reducing sugar and sugar alkali ratio decreased.the content of potassium and the ratio of potassium to chlorine increased first and then decreased;The yield of tobacco leaves under N3 and N4 treatments was significantly higher than that of other treatments.(3)The content of neutral aroma substance(except for neophytadiene)were as follows:the content of N2 treament was 169.72 μg/g,which was the hightest in the upper leaves,the content of N3 treament was 165.23μg/g,which was the hightest in the middle leaves;The content of neophytadiene:the content of N4 treament was 478.42μg/g,which was the hightest in the upper leaves,the content of N2 treament was 365.63 μg/g,which was the hightest in the middle leaves.(4)With the increase of nitrogencontent,the score of style,aroma quality,aroma amount,aftertaste and composite score of cigar increased first and then decreased,offensive odor and irritancy strengthened,concentration and strength increased.2.Effect of planting density on the quality of Luoning cigar The quality of tobacco leaves was better when the planting densit was 120cm*35cm(T3:1588 plants/667m2)and 120cm*40cm(T3:1389 plants/667m2).(1)The effect of planting denesity on Agronomic Characters in the early stage of field was not obvious,and the differences of agronomic characters increased after 45 days of transplanting.(2)With the decrease of tobacco density,the middle and upper leaves of each treatment were as follows:the weight of single leaf,leaf thickness,leaf weight and balanced moisture content will increase.The content of nicotine and total nitrogen increased,total sugar,reducing sugar and sugar alkali ratio decreased.the content of potassium and the ratio of potassium to chlorine increased first and then decreased;The content of neophytadiene increased gradually;The content of neutral aroma substance(except for neophytadiene)increased first and then decreased:the content of 2 treatment was the highest.The yield of tobacco under T1 treatment was significantly higher than that of other treatments.The yield of tobacco declined gradually,the production of T2 and T3 treatment was similar.(3)With the decrease of planting density,the style of cigar was more prominent.The scores of aroma quality,aroma amount,aftertaste and composite score first rose and then fell,while the strength and concentration increased,the offensive odor and irritation enhanced,and the sweetness weakened.3.The effect of remained leaves on the quality of Luoning cigarThe quality of tobacco leaves were the best when the number of remained leaves was 18P(P2).(1)There was no significant difference in agronomic characters between 30-45 days after transplanting.After topping(60days after transplanting),the difference of each indexes increased.The maximum leaf length,maximum leaf width and stem circumference decreased with the increase of remained leaves number,and the plant height and leaf number increased with the increase of remained leaves number.(2)With the increasing of remained leaves,the middle and upper leaves of each treatment were as follows:the weight of single leaf,the thickness of leaf and the weight of leaf decreased,while the the percentage of stem and the moisture content increased.The content nicotine,total nitrogen content and the ratio of nitrogen to alkali decreased,total sugar,reducing sugar content and the ratio of sugar to alkali increased.The content of neophytadiene decreased,while the content of neutral aroma substance(except for neophytadiene)increased,the yield of tobacco increased,and the difference between treatments was significant.(4)Increasing the number of remained leaves was beneficial to the decrease of tobacco leaves’ offensive odor and irritancy,as well as the decrease of concentration and strength.The score of cigar style,aroma quality,aroma amount and composite score increased first and then decreased.4.Changes of main chemical composition content and their effects on the quality of tobacco leaves in the fermentation process of cigar leaves with different modulation methods.(1)The change trend of chemical composition in the process of tobacco fermentation was similar under the three kinds of modulation.Among them,the total nitrogen content fiuctuated,the nicotine content showed a single peak on the left side,slightly decreased after fermentation,C3 treatment content was the highest;the change trend of total sugar and reducing sugar was roughly the same,and which decreased obviously in the early stage of fermentation,C1 treatment content was the highest.(2)In the process of fermentation of air-curing cigar leaves most of the neutral aroma substance increased first and then decreased,and the content was the highest at 14-21 days of fermentation.(3)In the process of fermentation,the scores of style,aroma quality,aroma amount,aftertaste and overall score of cigar increased first and then decreased,the offensive odor and irritation of tobacco decreased,the concentration and strength decreased.By comprehensive comparison,the traditional air-curing method(C3)has the best overall performance. |
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