Study On TSNAs Content Of Cigar Leaves At Home And Abroad And Accumulation Dynamics In Differen Production Links

This study collected 55 tobacco samples of different varieties of cigars at home and abroad,and analyzed their TSNAs content in different production areas and types,and explored the overall level of TSNAs content in cigar leaves.To clarify the key period of TSNAs accumulation in cigar tobacco leaves,field experiments were set up in Shifang,Sichuan Province for two consecutive years in 2019-2021 to explore the TSNAs of the main varieties in different links of tobacco leaf maturation,air-curing and fermentation and the accumulation and change law of their precursors.The main results are as follows:1.The variation of alkaloid content in cigar samples from different production areas was large,nicotinic content was 0.66%?10.02%,nicotinic content was 0.04%?0.79%,nicotinic conversion was 2.07%?28.01%.Except for the relatively high content of alkaloids in cigar leaves in China,there was no significant difference in alkaloid content in other production regions,and the total alkaloid content of filler was higher than that of wrapper and binder.The conversion of nicotine to nicotine in tobacco leaves of various producing areas and types of cigar leaves is more prominent.2.The total TSNAs range of cigar samples from different regions is 1.46?25.75?g/g,the average is 6.47?g/g.The NNN content is the highest,between 0.63?20.91 ?g/g,the variability is large;The NAT content between 0.21?8.64 ?g/g,the average is 1.94?g/g;The content of NAB and NNK is below 1.30 ?g/g.3.Correlation analysis showed that the higher conversion rate of nicotine in cigar leaves was the main reason for the higher contents of total TSNAs and NNN in filler,wrapper and binder.The varietal improvement of nicotine conversion traits and the optimization of alkaloid composition are important approaches to produce Chinese cigar tobacco with high quality and low harm.4.The accumulation of each TSNA component and total TSNAs of different varieties in the process of tobacco leaf maturation,air-curing and fermentation is very different.At the pre-maturation,air-curing and fermentation stages,the total TSNAs accumulation of Dexue 5 tobacco leaves with high nicotine conversion rate was 750.83?1189.63 ng/g?6678.97?9186.34 ng/g?7702.92?9406.90 ng/g,and the accumulation of NNN was the largest;the total TSNAs accumulation in the three stages of Dexue 3 with low nicotine conversion rate was lower' which was 153.53?208.26 ng/g?574.10?597.50 ng/g?647.40?1090.73 ng/g respectively.5.The accumulation ratio of each TSNA component and total TSNAs in different stages of different varieties of cigars was relatively small,the accumulation was less before maturity,the total TSNAs accumulation ratio was 4.96%?14.02%,the total TSNAs accumulation ratio was large during air-curing and fermentation,with 30.65%?48.22%and 40.71%?58.23%,then,the period of drying and fermentation is the important period of TSNAs formation and the key period of inhibiting the formation of different types of cigar leaves.