| With the step-by-step continuous flow translation barn, the changing rules of neutral aroma components contents in ripe tobacco upper-leaves during curing under different baking technology were studied, and the contents of chemical components, petroleum ether extract, and neutral aroma components of flue-cured tobacco leaves under different maturity and baking technology were determined. The result was showed as follows.1. In regular curing process, the total neutral aroma components contents (expect for neophytadiene) increased, gradually decreased, then increased again, then decreased and increased again in late curing period, and the contents of flue-cured tobacco leaves were higher than that before cured. Phenylalanine contents decreased, gradually increased, and decreased again when the contents reach the content-accumulated peaks with the cured processing. The contents of Maillard reaction components decreased, gradually increased, and decreased quickly again when the contents reach the content-accumulated peaks. Carotenoids contents were also increasing with the cured processing, and the contents increased quickly after 84h and reached a maximum after baking. Cembranoid aroma material changing of K326 and NC89 showed"W", and the solanone contents of Zhongyan100 increased at first, then decreased, gradually increased again when the contents achieved the lowest at 96h. Neophytadiene contents increased at first, then decreased, gradually increased again when the contents achieved the lowest.2. It was more beneficial to the accumulation of aroma components contents of the treatment of prolonging 12h at Later Yellowing Stage, and it was not suitable for prolonging too long time. Prolonging 12h of time is favourable, and the neutral aroma components contents could be improved on the range of 12h of time, or the neutral aroma components contents decreased beyond the range. The treatment of prolonging time at the late leaf drying stage goes against the accumulation of aroma components contents. Most of the kinds of aroma components contents decreased, and individual species of aroma components contents increased. The treatment of prolonging time at the later yellowing stage and the late leaf drying stage at the same time goes against the accumulation of aroma components contents of K326 and NC89, and was beneficial to the accumulation of aroma components contents of Zhongyan100.3. Different varieties response differently. With comparison of variety, the results showed that: In regular curing process, the trend of every kinds of aroma components contents changed the same, but the concrete details were different. The manifestations were that the time points when they achieved the lowest or the highest were different, and that the speed they increased or decreased was quickly or slowly. Under the three curing conditions, the aroma components contents changed differently with different varieties and different kinds of aroma components.4. Under the different Maturity and the same curing conditions, the total sugar, reducing sugar, total nitrogen and the nicotine contents was the highest in the over mature leaves and lowest in the immature leaves, and the starch contents was the lowest and petroleum ether extract contents was the highest in ripe leaves. Under the different curing conditions, the treatment of prolonging time at later yellowing stage was the best for the unripe leaves, and the total sugar, reducing sugar, total nitrogen, the nicotine contents was better than that of the conventional curing way and the difference between treatments reach the significant or extremely significant level. The method was also fit for the ripe leaves, and the conventional curing way was the best for the overripe tobacco leaves.5. In regular curing process, it was better for NC89 and K326 to gain coordinate chemical components contents when the harvest maturity is proper mature. The total nitrogen to nicotine ratio is more suitable in immature leaves and reducing sugar is the highest in over mature leaves, but other chemical components contents were best when the harvest maturity is proper mature. Harvesting at the proper mature, the treatment of prolonging time at later yellowing stage was the best for K326 and NC89, and prolonging time at the late leaf drying stage was suitable for Zhongyan100.6. Effects of curing conditions and maturity on the neutral aroma components contents were significant. Compared with the regular curing process, the treatment of prolonging time at the later yellowing stage was the best to improve the neutral aroma components contents in the immature leaves of the three varieties. The treatment of prolonging time at the later yellowing stage and the late leaf drying stage at the same time was the best for the ripe leaves. And in the over mature leaves, the treatment of prolonging time at the later yellowing stage was the best for K326 and NC89 and the treatment of prolonging time at the late leaf drying stage was the best for Zhongyan100 to increase the aroma components contents.7. In regular curing process, it was better for NC89 to gain higher aroma components contents when the harvest maturity is over mature. Then K326, the total contents of neutral aroma components were the highest in the over mature leaves. Harvesting at the unripe, the neutral aroma components contents were the highest in tobacco leaves after curing. Harvesting at the proper mature, the total contents of neutral aroma components were the highest with the treatment of prolonging time at the later yellowing stage and the late leaf drying stage at the same time of the three varieties, and the differences exist at every kinds of aroma components. Phenylalanine contents were the highest on the treatment of prolonging time at the late leaf drying stage of NC89, and phenylalanine contents, the solanone contents and the neophytadiene contents were the highest on the treatment of prolonging time at the later yellowing stage of K326. Also, the solanone contents and the neophytadiene contents were the highest on the treatment of prolonging time at the later yellowing stage of K326 of Zhongyan100. |
