ABSTRACT In this work, the effect of oxidation pretreatment on the enzymatic hydrolysis of cellulose in tobacco stems was evaluated. A comparison was made between the effect of H2O2 pretreatment and conventional alkali pretreatment on the weight loss of cellulose, lignins and hemicelluloses of tobacco stems. The effects of H2O2 concentration, pretreatment time and temperature on the enzymatic hydrolysis of tobacco stems were investigated. This pretreatment could give a higher recovery of cellulose and better removal of lignin and hemicellulose than alkali‐only pretreatment. Compared with the untreated stems, the yield of reducing sugar pretreated by H2O2 pretreatment (pH 11.5, 0.6% H2O2) for 9 h at 60C increased 347.2%. The results of scanning electron microscope and X‐ray diffraction analysis also showed that the structural and crystalline properties of the tobacco stems were changed by pretreatment, and they were in favor of the following enzymatic hydrolysis. The optimal pretreatment conditions were 60C of temperature, 0.6% of H2O2 concentration and 9 h of time, which were calculated by orthogonal experiments. PRACTICAL APPLICATIONSPretreatment on lignocellulosic materials to disrupt the recalcitrant structure is helpful for their bioconversion into low‐molecular weight substances. The tobacco stems were pretreated by H2O2 oxidation before subjecting to enzymatic hydrolysis by cellulase in this work. This pretreatment was confirmed effectively to improve the recovery of celllulose, and helpful to remove lignin and hemicellulose. Moreover, the yield of reducing sugar produced by cellulase hydrolysis was apparently improved. These results were helpful for the extensive development of tobacco stems.

In order to investigate expansive tobacco stem granule multiple filter's application effects,expansive tobacco stem granule multiple filter and acetate filter without expansive tobacco stem were added into cigarette to carry out contrast experiment.The results showed that expansive tobacco stem granule can decrease tar,promote aroma,decrease irritancy and reduces B(a)P from cigarette mainstream smoke by 12.13%.

In order to improve the usability of tobacco stem,the effects of treatments with dilute NaOH and H2O2 solution on the filling power,cell wall substance and smoking quality of tobacco stem were tested. The results showed that the optimal treatment conditions were:dipping in solution of 1.0% NaOH and 1.0% H2O2 at 70 ℃ for 1.5 h,under which the contents of cell wall substances,lignin,total nitrogen and total sugar in treated stem decreased by 12.71,2.14,1.24 and 10.28 percentage points,respectively; while stem's moisture content and filling power increased by 4.02 percentage points and 10.34%,and its smoking quality obviously improved.

采用轮廓分析法对六种市场占有率较高的品牌卷烟进行评吸,并对其相应的致香成分进行了气相色谱/质谱定性定量分析,为今后研究香味感官特征与致香成分的关系提供了科学依据。

The qualitative and quantitative analysis of nicotine in water extract of tobacco products were performed by liquid chromatography/electrospray ionization linear ion trap tandem mass spectrometry (LC-ESI-ITMS/MS) in positive ion mode. The proposed structure of major fragments In the MS/MS spectrum of nicotine was analyzed. Mass spectrometer was first tuned with standard solution of nicotine to obtain optimum parameters for detecting, then quantitation of nicotine was carried out in selective reaction monitoring ( SRM) scan mode. Limit of detection ( LOD) of the method was 0.21 mu g/L. Recovery was 99% - 105% and precision observed in three different concentration levels was from 0.64 to 0.72% (RSD). The goal of rapid quantitation was achieved by using a short. high performance chromatography column with high throughput.

The preparation and determination of major,micro,and trace metal elements in tobacco leaf,cigarette materials,and cigarette smoke were reviewed.

采用阴离子交换色谱-积分脉冲安培检测法分离测定了烟草料液中山梨醇、葡萄糖、果糖、蔗糖和麦芽糖,研究了山梨醇和糖在阴离子交换色谱中的保留行为。采用优化的水和氢氧化钠二元梯度淋洗条件,C arboPac PA10阴离子交换色谱柱进行分离,积分脉冲安培检测器检测一次进样测定烟草料液样品中的山梨醇、葡萄糖、果糖、蔗糖和麦芽糖。各组分在测试条件下线性关系良好,线性范围为0.005~20m g/L,检测限为0.2~1.0μg/L,加标回收率为95.1%~102.4%,相对标准偏差为1.2%~1.9%。

In order to investigate the influence of smoking regime on the yields of tar, nicotine and CO in cigarette smoke, 16 cigarette samples were smoked under different smoking regimes, including ISO standard method and alternatives A and C proposed by WG9 of ISO/TC126. The results showed that while comparing with ISO standard, the proposed regimes gave tremendously high yields of tar, nicotine and CO but didn’t widen discrepancy between the measurements.