| In order to explore the curing characteristics of Yunyan 116 in subtropical warm and moist climate,the dark box test and curing test were combined with Yunyan 87 as the control.In dafang county,Bijie city,the characteristics of yellow and brown,color characteristic value and water content in tobacco leaves were studied in dark box,and the variation of color,shape,water content,dry matter,main enzyme activity and main chemical composition in tobacco leaves during curing were also studied.1.Dark box test results show that:(1)The total yellowing time of Yunyan 116 is 72 h,which is the same as that of Yunyan 87,and meets the standard of good curing ability;The Browning time of Yunyan 116 is about 112 h,about 29 h earlier than that of Yunyan 87.Compared with yunyan 87,yunyan 116 has better curing resistance,but its curing resistance is slightly worse and only reaches the standard of medium curing resistance.(2)The color value of Yunyan 116 was similar to that of Yunyan 87,with L and A values increasing continuously,B and C values increasing first(before 60h)and then decreasing(after 60h),while H value showed a decreasing trend.The color values of Yunyan 116 and Yunyan 87 were significantly different at 12h(L,B,C values),24h(A,B,C values)and 48h(B,C values),respectively.(3)SPAD values of Yunyan 116 and Yunyan 87 showed a slow-fast-slow downward trend;Compared with Yunyan 87,the SPAD value of Yunyan 116 decreased significantly faster from 12 h to 48 h.(4)The water loss rates of Yunyan 116 and Yunyan 87 showed a trend of fast at first and then slow down gradually;Compared with the two varieties,the water loss rate of Yunyan 116 was faster than that of Yunyan 87.The water loss rate of Yunyan116 was 38.09% at 72 h,3.24 percentage points higher than that of Yunyan 87,and was 61.49% at 144 h,9.97 percentage points higher than that of Yunyan 87.2,curing test(0H-144 h to the end of fixed color)results show that:(1)The SPAD value and pigment variation of Yunyan 116 were similar to that of Yunyan 87,and the chlorophyll degradation amount and degradation rate were close to that of Yunyan 87.Both varieties met the standard of being easy to cured.(2)The tobacco shrinkage rate of the two varieties showed a trend of first increasing and then decreasing,and the longitudinal shrinkage rate was less than the transverse shrinkage rate than the area shrinkage rate;The shrinkage rate of yunyan116 was slightly higher than yunyan 87.(3)The water content of the two tobacco cultivars showed a decreasing trend of first slow then fast,while the dry matter showed a slow-fast-slow decreasing trend;Compared with Yunyan 87,the water loss and dry matter loss of Yunyan 116 were2.22 and 1.18 percentage points higher,respectively.There was little difference in water loss balance between the two varieties,which both met the requirement of good curing ability.(4)the two varieties of tobacco PPO,SOD activity and MDA content,respectively,show up-down-up-down,slow at first and lowered later-fast-slow upward trend;The average PPO activity and MDA content of Yunyan 116 were 0.08 U and 8.87 U higher than those of Yunyan 87,respectively,while the average SOD activity was 43.3U lower.Yunyan 116 has medium curing resistance,slightly worse than Yunyan 87(better curing resistance).(5)The contents of nicotine,potassium,petroleum ether extract and total phenol increased slowly,the contents of two sugars increased rapidly,while the contents of total nitrogen,protein and starch decreased slowly.Compared with Yunyan 87,the contents of starch,disaccharide and petroleum ether extract of Yunyan 116 were slightly higher,while the contents of total nitrogen,protein,nicotine,potassium and total phenol were slightly lower.(6)Compared with Yunyan 87,the average price and the rate of superior tobacco were 1.59 yuan /kg lower and 9.48% lower,while the rate of medium tobacco and the rate of mixed color tobacco were 5.47% and 4.07% higher,respectively.The appearance grade quality of Yunyan 116 was lower than that of Yunyan 87.3.Correlation analysis results:(1)Pearson correlation analysis showed that there was a significant correlation between water content and yellowing speed,color value,SPAD value and pigment of tobacco leaves in both dark box test and curing test.There was a significant correlation between water content and main enzyme activities,as well as between main chemical components.(2)Principal component analysis showed that the contents of total sugar,reducing sugar,dry matter,protein and total nitrogen could be used as representative indexes to measure the quality of tobacco chemicals,and these components were important indexes to affect the quality of tobacco chemicals.(3)Grey system analysis showed that the average value of PPO activity was most closely related to MDA content,carbohydrate content,medium smoke rate and variegated smoke rate;The mean value of SOD activity was closely related to the content of nitrogen compounds,the average price of cured tobacco and the rate of superior tobacco.From the stage analysis,SOD activity affected the average price of cured tobacco in yellowing stage and the rate of superior tobacco in fixed color stage.PPO activity in fixed color stage had influence on the quality indexes of all grades of cured tobacco,MDA content in fixed color stage had the greatest influence on the average price and the rate of mixed color tobacco.On the whole,Yunyan 116 has good curing ability and moderate curing resistance.Compared with Yunyan 87,yunyan 116 has similar curing ability but slightly worse curing resistance.Yunyan 116 has medium and upper curing characteristics. |
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