| According to the studies on accumulating rule of nitrate, nitrite, nicotineand nornicotine under the treating conditions of different baking and chemicals, there are conclusions as bellow:1 The increase or induce of nicotine after baking is related to the baking conditions during yellowing :The content of nicotine after baking is lower than that before baking during yellowing of higher temperature and higher humidity or higher temperature and lower humidity, however, The content of nicotine after baking is higher than it is before baking during yellowing of lower temperature and higher humidity or lower temperature and lower humidity. Lower temperature benefits to the accumulation of nicotine and higher temperature doesn't benefits to the accumulation of nicotine. The influence of flue-curing humidity on the content of nicotine hadn't obvious rule. The content of nicotine declines gradually during the color-fixing. Rate of nicotine decline under lower humidity color-fixing is fastest, and that of moderate humidity color-fixing is faster, and high humidity color-fixing is slower. The content of nicotine doesn't change basically during drystem2 Nornicotine mainly form during the process in baking. It is benefit to the forming and accumulation of nornicotine under higher temperature and higher humidity conditions during yellowing. The order of nornicotine content increase after baking is :firstly ,higher temperature and higher humidity secondly ,lower temperature and higher humidity ,thirdly ,higher temperature and lower humidity ,at last lower temperature and lower humidity content of nornicotine gradually increased at the early corour-fixing stage ,speed order of increasing is :firstly ,higher humidity , moderate humidity lower humidity .The content of nornicotine at later corour-fixing stage decrease gradually .The content of nornicotine is indeclinable at drystem stage 3The average value of nicotine and the nornicotine at every stage of 4 kind baking states were negative correlation of linearity by recursive analysis of linearity, Y=1.962542-4.92044X(Y representing the content of nicotine, X representing the content of nornicotine), and F=5.26, they reached significant level, it showed that the nornicotine was mainly from the decompose of nicotine, and the reduce ofnicotine content caused the reduce of nornicotine at a certain extent.4 The content of nitrate gradually increases during yellowing and it reach to highest content in the end of yellowing, and then descend quickly. The speed of nitrate increasing is different. The speed of nitrate increasing under lower temperature and higher humidity, lower temperature and lower humidity is higher than higher temperature and lower humidity, higher temperature and higher humidity. The speed of nitrate increasing after baking shows the same result. The content of nitrate gradually increases during color-fixing, and the accumulation of nitrate was less influenced by humidity conditions.5 the content of nitrite increased gradually during yellowing and contents of nitrite is hightest in the end of yellowing, the order of increase about nitrite contents during yellowing is lower temperature and higher humidity, lower temperature and lower humidity, higher temperature and higher humidity ,higher temperature and lower humidity. The contents of nitrite during colour-fixing gradually decline .the speed of declining is lower humidity,moderate humidity,higher humidity.6The content of dissociative nicotine and associative nicotine after baking is higher than before baking, on the contrary ,the contents of those after baking is lower than before baking, lower temperature not only benefit to accumulation of dissociative nicotine but also benefits to that of associative nicotine. Lower humidity is beneficial to accumulation of dissociative nicotine and is not beneficial to accumulation of associative nicotine.7.the enzyme activity of demethylase in flue-cured tobacco NC89 increased gradually at yellowing stage in the condition of slow yellowing at low...
|
PDF Full Text Request