Study On Quality Characteristics And Enzymatic Improvement Of The Major Tobacco Cultivars In Shaanxi

China is the world's largest tobacco cultivation country,and Qinling Mountains is also an important tobacco cultivation area in Shaanxi.However,compared with Yunnan,Guizhou and other areas,industrial suitability of Shaanxi tobacco is not great.Particularly,there are problems of insufficient aroma,heavy green mixed gas and soil mixed gas,and a large inventory of tobacco leaves,which seriously restricts the economic benefits of tobacco.In this paper,the major tobacco cultivars of Shaanxi were collected as test materials in 2018and 2019.And the standard module tobacco of Shaanxi Tobacco Technology Center was used as the control.Sprayed compound enzyme preparation(?-amylase,glucoamylase,pectinase,cellulase,neutral protease and papaya protease)on tobacco leaves for enzymatic hydrolysis,which was based on the analysis of chemical composition and volatile aroma compounds.To evaluate the style characteristics and aroma quality of tobacco leaves treated with different enzymes through sensory evaluation,compare the changes of chemical indicators and aroma components before and after the enzyme treatment,optimize the treatment conditions of enzyme preparations,which was devoted to improving the quality of tobacco leaves,and provide a theoretical reference for the quality and efficiency of Shaanxi tobacco leaves.The main findings are as follows:(1)The tobacco samples of Shaanxi in 2018 were analyzed,the sugar content of different flue-cured tobacco,redried lamina,and standard modular tobacco had little difference.The nitrogen-base ratio of Baoji X3F,Baoji C3F and Shangluo B3F was not satisfied,there was a large gap with the standard modular.The ratio of two sugars of Baoji X3F and SXTC was lower,the content of potassium and chlorine was generally low in soil of Shaanxi.Volatile aroma detection results showed that different flue-cured tobacco and redried lamina was detected a total of 148 kinds of aroma compounds.The total aroma of Baoji X3F was the lowest,but that of Shangluo B3F was the highest.Neophytadiene is the most abundant aroma component in tobacco.Cluster analysis results showed that the quality of Ankang B3F was better and close to the middle grade tobacco.The similarity between Baoji X3F and standard module tobacco was the smallest,followed by Shangluo B3F.(2)According to the results of cluster analysis,Baoji X3F,Shangluo B3F,and SXTC were selected to treat with enzyme preparation.And the enzyme tests were designed by U5(5~6)uniform table.Baoji X3F was treated with T2,T4 tests,the results showed that the reducing sugar content was increased,the content of volatile aroma was greatly increased,the sweetness was increased,the smoke was delicate and soft,and the sensory quality scores were higher than the control.Shangluo B3F was treated with T1,T4,T5 tests,the content of total sugar and reducing sugar increased,the sweetness was improved,the fumes were reduced,the smoke was more delicate,and the sensory quality scores were better than the control.SXTC redried lamina was a formula finished tobacco,with a more coordinated chemical composition,which was not suitable for enzyme treatment.(3)The flue-cured tobacco leaves from different areas,grades,and varieties in Shaanxi Province in 2019 were analyzed.The results showed that the sugar,nicotine,total nitrogen,starch,and ash content of tobacco in different producing areas were significantly different.The sequence of sugar content from high to low was middle,lower,and upper grade.The sequence of nicotine and total nitrogen content from high to low was upper,middle,and lower grade.The starch content of the lower grade was lower than that of the middle and upper grades.The ash content of middle grade was lower than that of the upper and lower grades.In a word,the chemical quality of tobacco leaves in Hanzhong and Ankang was better than that in Shangluo,and the tobacco quality of the middle grade was better than the upper and lower grades.The aroma results showed that Ankang C3F and Ankang B2F had the highest total aroma content,while the remaining tobacco leaves had little difference in aroma content.The aroma content of carotenoids and cembranes degradation products of standard modular was significantly higher than that of flue-cured tobacco.But the amount of phenylalanine degradation products and chlorophyll degradation was lower than that of flue-cured tobacco.It was found that in the cultivation of tobacco areas in Shaanxi,the quality of Yunyan97 was greater than Yunyan99.(4)The results showed that the effect of middle and lower grade tobacco with compound enzyme treatments was not obvious.Hanzhong B2F and Ankang B2F were treated with T1,T4,and T5 tests,it was found that the ratio of two sugars increased,the sugar-base ratio was more coordinated,and the chemical quality was improved.Hanzhong B2F was treated with T1 and T5 tests,it was found that the total aroma of tobacco leaves increased by 10.8%and 33.4%,respectively.The Hanzhong B2F sensory quality score of T5treatment was the highest,which was characterized by slight improvement of the aroma,followed by the T1 test,which was slightly higher than the control.Ankang B2F was treated with T5 test,the content of total aroma was not improved,but the aroma quality was improved,the sensory quality score was higher than that of the control,which showing that the aroma was fragrant,and the softness was increased.