基于Tabu搜索的贝叶斯网络在烟叶香型评价中的应用

烟叶香型通常是靠人的嗅觉评定的,评定结果的准确性往往难以保证。针对该问题,国内外建立了BP神经网络等感官评估模型,但识别效率不高。根据烟叶中化学成分与烟叶香型关系,使用基于Tabu搜索的贝叶斯网络建立烟叶香型识别模型。实验结果表明,使用该方法能得到较好的贝叶斯网络结构,与BP神经网络等方法相比训练效率更高,分类的结果也更加准确。     

荷叶提取液中生物碱的缓蚀性理论研究

用密度泛函理论中的B3LYP方法，在3—21G和6—311G基组水平上，系统研究荷叶中生物碱的缓蚀性能。结果表明：鹅掌揪碱〉去氢荷叶碱〉睡莲碱〉去氢番荔枝碱〉去氢莲碱，它们静电势分布于环平面，硬度较小，能隙较小，电子转移数较高，同时电负性和亲电性值也小，对于吸附位，带酮基的分子的静电势主要集中在酮基氧原子上。     

分形树叶脉络建模算法研究

研究分形理论在计算机图形学中的应用,基于分形关于生成技术的自然景物模拟.     

Template removal in MCM-41 type materials by solvent extraction: Influence of the treatment on the textural properties of the material and the effect on its behaviour as catalyst for reducing tobacco smoking toxicity

In this work a series of MCM-41 catalysts have been prepared by eliminating the template by calcination and by different extraction treatments. The extracted samples were also calcined and aluminium ion exchanged. A hydrothermal stability test of the final materials has also been performed. N₂ adsorption isotherms, NH₃ thermal desorption, X-ray fluorescence, X-ray diffraction, ²⁷Al NMR and thermogravimetry of each material have been determined in order to establish the influence of the procedure used for template elimination on the physicochemical and textural properties of the material. Moreover, the ability of the different catalysts prepared for reducing the toxicity of the mainstream smoke evolved when cigarettes are smoked has been checked too. The results obtained show that the final properties of the catalyst depend noticeably on the experimental conditions used in the template extraction process (i.e., the solvent selected, the solvent:catalyst ratio, the temperature, the contact time and the number of successive extraction steps). Thus, the adequate selection of such conditions permits a material to be obtained with properties very similar to that of the calcined MCM-41 material. As a conclusion, the material showing the best properties, among the catalysts studied in this work, produces a mean reduction of the yield of the different compounds analyzed in the gases and in the condensed products retained in the filters and in the traps of around 35%, 75% and 45%, respectively, which are slightly higher than the values corresponding to the calcined MCM-41 used as reference (i.e., 25%, 56% and 40%, respectively). These reductions results in an increase of the amount of ashes of around 2 mg/cigarette due to the presence of the catalyst.     

Influences of ripening stages and extracting solvents on the polyphenolic compounds,antimicrobial and antioxidant activities of blueberry leaf extracts

This study investigated polyphenols, antimicrobial and antioxidant activities of blueberry leaf extracts harvested at three fruit ripening stages (immature, semi-mature, and commercial-mature) and extracted by three solvents (95% ethanol, 70% acetone, and 100% methanol). Quercetin, kaempferol, gallic, protocatechui, caffeic, vanillic, syringic, p-coumaric, and ferulic acids were identified in the extracts with varied amount depending on ripeness stage and extraction solvent. Protocatechui and ferulic acids were not detected at semi-mature samples, and none protocatechui, syringic and p-coumaric acids in ethanol-extracts from commercial-mature samples. All extracts exhibited antimicrobial activity against Escherichia coli and fungi, but only semi-mature and commercial-mature samples were against Listeria monocytogenes and Staphylococcus aereus. Methanol- and acetone-extracts had higher polyphenol content, DPPH and reducing power than those of ethanol-extracts, whereas opposite trend was observed in ORAC values. These results indicated the potentials of using blueberry leaf extracts as natural antimicrobial and antioxidant substance for food applications.     

Antifungal Activity of Crude Extracts of Coffee and Spent Coffee Ground on Areca Palm Leaf Sheath (Areca catechu) Based Food Packaging

This study observed the antifungal activity of crude coffee extract (CCE) and crude spent coffee ground extract (CSCGE) against Aspergillus sp., Aspergillus flavus, Aspergillus niger, Penicillum citrinum, Penicillum chrysogenum and Eurotium amstelodami on the surface of an areca palm leaf sheath (Areca catechu). The agar dilution method was employed to determine the minimal inhibitory concentration (MIC) of the CCE for the first, second and third extractions and CSCGE for the first and second extractions in malt extract agar at concentrations from 50 to 500 μg/ml. A mould test was then performed on durian paste product wrapped with the areca palm leaf sheath treated with the second CSCGE at its MIC. Gas chromatography‐mass spectrometry (GC‐MS) was performed to find the major components of the CCE and CSCGE and to measure the total phenolic content. For the second CSCGE treatment on the areca palm leaf sheath, the following qualities were studied: mould growth, wettability, measurements of hardness and thickness and a Fourier transform infrared spectroscopy scan. It was found that the CCE and CSCGE MICs from the first and second extractions ranged from 100 to 230 μg/ml and from 300 to 460 μg/ml, respectively. In addition, the MICs showed the capability of CCE and CSCGE to provide protection against mould growth on the leaf sheath for at least 21 days in comparison with the control (3 days) during storage at accelerated conditions (25 °C and 100% relative humidity). Shelf life of durian paste product wrapped with areca palm leaf sheath treated with the second CSCGE at 460 μg/ml was extended from 3 days to 21 days under storage condition of 30 °C. Caffeine was the main constituent of CCE (79.69%) and CSCGE (84.92%). Also, the total phenolic content of CCE and CSCGE measured were 0.640 and 0.981 mol ferulic acid 100 g^?1, respectively. This study has demonstrated that the first and second CCE and CSCGE were capable of inhibiting mould growth under both in vitro and in vivo tests. Copyright © 2015 John Wiley & Sons, Ltd.     

大叶桉叶中没食子酸的提取研究

以大叶桉叶为原料,选择合适的溶剂提取大叶桉叶中的没食子酸。以高效液相色谱为检测手段,用蒸馏水进行提取。通过提取时间、提取温度、固液比、提取次数4个单因素实验,确定正交试验的水平,优化提取工艺。通过正交试验确定没食子酸提取量的影响因素大小是:提取温度提取时间提取次数固液比。最佳工艺条件是:提取时间150min,提取温度100℃,固液比为1∶60,提取次数为3次,在此工艺条件下,没食子酸提取量为5.27mg·g-1。     

艾叶中抑菌物质的提取及抑菌作用研究

以自来水作溶剂,对艾叶中抑菌物质的提取条件进行了研究,得到了最佳提取条件。将该物质对几种常见的食品微生物进行抑菌活性实验,发现其对细菌的抑制效果明显,酵母次之,对霉菌效果一般;最低抑菌浓度(Mic)试验表明,该物质Mic为50%。该物质抑菌pH范围为3～6,且热稳定性不好。     

品种及平衡施肥量对初烤烟叶化学成分的影响

研究了不同品种以及平衡施肥量对初烤烟叶 8种化学成分及两个比值的影响。结果表明 :施肥量间烟叶总N、总糖、还原糖及糖 碱比、施木克值呈显著差异 ,其余成分差异不显著。随着施肥量的增加烟叶总N含量提高 ,总糖、还原糖、糖 碱比、施木克值降低 ;各品种间除烟碱含量外 ,其余成分和比值差异显著 ;二因素对烟叶化学成分的交互作用不显著     

顶空-固相微萃取-气相色谱-质谱分析马铃薯茎叶中挥发性成分

首次用顶空-固相微萃取-气相-质谱技术对马铃薯茎叶的挥发性成分进行了萃取和分析。共检测出71个成分,鉴定出占总成分91.27%的45种成分。主要为萜类化合物（28.80%）和芳香族化合物（21.84%）。其次为饱和脂肪烃类占7.70%。酯类化合物和醇类化合物分别为4.35%和4.79%。酮类化合物和羧酸分别为3.45%和3.53%。醛类化合物为2.84%。