The Analysis Of Related Compounds In Maillard Reaction During Tobacco Curing Process

There are many factors that will not only become scientific, as well as effective controlling techniques and means to improve the aromatic quality of tobacco, the raw material availability and industrial creativity, during tobacco production and processing, but also provide experimental basis for division of tobacco yield districts, which are the changes of Maillard reaction related compounds during Tobacco curing process, the changing rules of these compounds with different species, the different leaf positions and different maturity during the curing process, and changes of modulation in the baking process. This study is based on the research of tobacco K326, Yunyan 85 and HD which are main cultivated species in China. HPLC(High performance liquid chromatography) technology have been applied hence ensuring a timely and efficient extraction, store as well as accurate determination of flue-cured tobacco in the rapid separation of chlorogenic acid and rutin. Therefore,the limitations of outdoor research can be effectively avoided, hence ensuring the dynamics, promptness and accuracy of the data. The changing rules have been gained that the major pre-materials of Maillard reaction contents of the same leaves' position of different species, the same species in different leaves' position and the different maturity of cured tobacco leaves.The conclusion is made through the study of statistical analysis and comparison of the content of different species, different leaves' positions and different maturity of the major tobacco curing process of Maillard reaction pre-materials. The major findings are as follows:(1) The variation of leaves' water content is similar to that of relative humidity of tobacco curing barn, even by different curing technologies. In other words, it is simultaneous that the change of leaves' water content and the decrease of relative humidity in barn. Relative humidity of curing barn directly affects the dehydrating rate of tobacco. Thus, the decline are closely related in rate of leaves' moisture content and relative humidity range of barns. Significant difference exists in water loss rate due to the curing process of the different species, leavses' position and different maturity. HD has relatively slower rate of water loss, comparing with clouds HD and Yuyan 85, K326 in the baking process. Because of its thicker leaves, relatively higer water content, higher accumulation rate of dry matter, and its leaves' internal bound water content is high, being sensitive to changes in temperature and humidity. Therefore, the baking of HD was generally more difficult.(2) The change of the content we consistent, in three mentioned species, of which were free amino acids in tobacco, nicotine, and proline. With the conduct of baking, these contents increase gradually.The total free amino acid content of the Yunyan 85 was overall low, among the three genotypes of tobacco. Whereas the content of free amino acids in leaves of K326 and Yunyan 85 boasts the largest increase before and after baking.K326 leaves' proline content were lower than those of HD, Yunyan 85 tobacco when 48h before and 72h after baking. And the HD tobacco boasts the largest nicotine content, comparing with the flue-cured tobacco K326 and Yunyan 85. Free proline content doubled after baking, comparing with that before baking, in the same variety of tobacco leaves. The free amino acid content was not significant in different parts of tobacco leavs, the average content is: middle leaves> upper leaves> lower leaves; the variation of its nicotine content was similar that the nicotine content was also not significant in the different parts of tobacco leaves, and the average content is:upper leaves> lower leaves> middle leaves. The changing rules were similar in leaves of different maturity, but there are different cumulative rate. The largest increase of free amino acid content, before and after baking, exists in the ripe and overripe tobacco leaves. By baking tobacco leaves, the total free amino acid content, and Amadori compounds related to proline synthesis are increased comparing with those before baking. The analysis showed that there is seldom significant changing level of free amino acids associated with the proline content among the three varieties of tobacco during the curing process. The total free amino acid and proline content were positively related in tobacco of different maturity during the curing; and those of the ripe, mature leaves have a very significant positive correlation up to 0.01.(3) The leaves' position and maturity of the three species showed a similar law. The total content of soluble sugar accumulated rapidly in the early period of baking; after reaching its peak value, it then decreased slowly, and finally stabilized to end soon. The leaves' sugar content increases obviously before 96 hours, in the baking process.The total soluble sugar and reducing sugar in cured leaves reduced 2 to 5 times on average, comparing with those of the pre-roasted. However, the impact was evidently influenced by the position; the central lobes has the maximal increase, the upper leaves ranks the second, and lower leaves is the minimal. Maturity exerts a great impact on reducing sugar content of cured leaves, which means with the increase of maturity, there is relatively higher reducing sugar accumulation. Analysis showed that the total sugar and reducing sugar content was significantly positively correlated in different species, leaves' position and maturity during the curing process.(4) HD has the most total phenol, chlorogenic acid and rutin in former concentration, followed by K326, and Yunyan 85 has the minimum.The content of these compounds in upper lobes and the middle lobes was significantly higher than that of the lower parts. The total phenol, chlorogenic acid and rutin increased with the increase of maturity, but the content of these compounds is inclined to reduce when the maturity reached the highest value, hence it is appropriate to harvest the leaves in the middle part after full maturity. The variation rule of Chlorogenic acid content in the baking process is similar to that of total phenol, being significant positive correlated. The total phenol and rutin content was significantly correlated in K326, Yunyan 85 leaves, the correlation coefficient of which are 0.926** and 0.893**. According to the analysis of Polyphenols changes during the baking and the chemical composition of conventional dynamic correlation, in addition to HD, whose total phenol content of nicotine, chlorogenic acid content showed a significant positive correlation, the correlation was not significant of other chemical indicators and changes in polyphenol content. When different tobacco leaves were cured, polyphenols had no significant correlation with other chemicals, except for the following ones:significantly negatively correlated as the chlorogenic acid and proline content in the lower leaves, the chlorogenic acid and total free amino acid content in the upper leaves; and significant positive correlated as the nicotine content and the total phenols. When the lower leaves of K326 in the baking process, which boast different maturity, in addition to nicotine in overcooked tobacco, the other chemical indicators and the changes in polyphenol content had no significant correlation.