均匀设计优化香草兰中香兰素的超临界萃取工艺

研究超临界Co2萃取香草兰豆荚中香兰素等香料成分的工艺,以香兰索产量为检测指标,使用均匀设计-偏最小二乘法回归分析,优化萃取工艺的压力、温度、时间和夹带剂乙醇的体积4个因子,确定最佳提取工艺条件为:压力41.10 MPa,温度50℃,时间180 min,夹带剂体积5.0 mL,此时,20g香草兰原料萃取香兰素的理论产量为177.211 mg.对该技术应用于香草兰中香兰素提取产业化的前景和可行性进行分析探讨.     

利用SPME-GC×GC/TOFMS对香草兰中挥发、半挥发性成分萃取与分析研究

利用固相微萃取(SPME)法萃取香草兰中挥发和半挥发性的成分,再结合全二维气相色谱/飞行时间质谱(GC×GC/TOFMS)技术进行定性分析。试验共鉴定出香草兰中181种挥发、半挥发性化合物,其中含量较高的成分主要有香兰素、呋喃甲醛、(2S,3S)-(+)-2,3-丁二醇、邻甲氧基苯酚、2,3-丁二醇、苯酚、正己醛、(2R,3R)-(-)-2,3-丁二醇、对羟基苯甲醛、3-甲基丁酸、2,3,5,6-四甲基吡嗪、3-羟基-2-丁酮、香草酸、壬醛、正己酸、1-辛烯-3-酮。结果表明,GC×GC/TOFMS高分辨率和高灵敏度的特点非常适合复杂组分体系的定性分析。     

海南省香草兰主要病虫害现状调查

为摸清海南省香草兰主要病虫害种类及危害情况,2008年3月～2009年12月对海南省琼海、万宁、定安、屯昌、儋州等5个市(县)共10个乡镇进行了调查,结果表明:目前为害海南香草兰生产的主要病虫害有8种.其中病害6种,分别是香草兰根(茎)腐病、香草兰疫病、香草兰细菌性软腐病、香草兰花叶病、香草兰白绢病和香草兰炭疽病;虫害有2种,分别是香草兰拟小黄卷蛾和可可盲蝽.分布广且为害严重的是香草兰根(茎)腐病、香草兰疫病、香草兰细菌性软腐病和香草兰花叶病.     

菠萝蜜种子淀粉制备香草兰微胶囊的工艺研究

以菠萝蜜种子淀粉为壁材,采用饱和水溶液法制备香草兰精油微胶囊,以包埋产率为指标,采用响应面分析法对微胶囊的包埋条件进行优化探讨。结果表明:5个单因素中,影响最显著的因素为壁芯材比例、包埋温度和包埋时间。响应面优化得到香草兰精油微胶囊的最佳工艺条件为壁芯材比例为7.5∶1;包埋时间72 min;包埋温度54℃,此条件下的包埋产率为(95.46±0.2)%,包埋率为(76.35±0.6)%,载油量为(27.73±0.3)%。试验证明,此条件结果与模型预测值相吻合,此工艺条件可为菠萝蜜种子淀粉包埋香草兰精油微胶囊工艺提供理论依据。     

香草兰豆挥发性香气成分比较研究与电子感官图谱绘制

采用感官评定法,结合电子鼻（E-Nose）和顶空固相微萃取-气-质联用（HS-SPME-GC-MS）技术,分析不同产地、年限、等级香草兰豆的挥发性成分,建立香草兰豆种类和品质快速检测方法。结果表明：香草兰豆感官评分由高到低依次为海南2013年一级豆、海南2013年二级豆、科摩罗2013年二级豆、汤加2013年二级豆、海南2012年二级豆、海南2013年三级豆、海南2010年二级豆、海南2011年二级豆。不同产地、年限、等级的香草兰豆挥发性成分的整体信息在电子鼻主成分分析（PCA）图谱中有显著差异。海南2010、2011和2012年二级香草兰豆分别被检测出65、60和62种挥发性成分,相对含量最多为香草醛,分别为60.00％、57.00％、62.78％;不同种类香草兰豆的芳香族类、醛类、酮类、酸类、醇类、杂环等六大类香气化合物相对含量有明显差异。在此基础上绘制电子鼻指纹图谱,利用电子图谱可以快速区分香草兰豆的种类和品质。     

冷冻-溶解联合外源酶处理香草兰鲜豆荚对香气成分的影响研究

香草兰是兰科多年生藤本攀缘植物,经过发酵后散发出多种芳香成分成为重要的风味原料。然而,传统发酵生香时间长,香气成分转化率低。本试验考察冷冻-溶解联合不同外源酶处理对香草兰鲜豆荚主要香气成分的影响。结果表明：外源酶不仅可以提高香兰素的含量,还可提高其前体物质-葡糖香草醛的转化率。在此基础上,对比空白样品,所有冷冻-溶解联合外源酶处理后的香草兰中香兰素、对羟基苯甲醛、对羟基苯甲酸和香兰酸含量均显著增加,经过纤维素酶-果胶酶-β葡萄糖苷酶处理后的香兰素、对羟基苯甲醛、对羟基苯甲酸和香兰酸含量最高为5.660％、0.089％、0.069％和0.101％;相比于传统发酵和普通外源酶处理,所有冷冻-溶解联合外源酶处理香草兰鲜豆荚均显著增加香兰素含量（p<0.05）,而纤维素酶-果胶酶-β葡萄糖苷酶、果胶酶-β葡萄糖苷酶、纤维素酶-β葡萄糖苷酶、纤维素酶-果胶酶、果胶酶显著增加对羟基苯甲醛、对羟基苯甲酸和香兰酸含量（p<0.05）。     

葵花子油不同提取工艺的比较

通过比较超临界CO3提取葵花子油的均匀设计实验和微波、超声波诱导提取葵花子油的正交实验结果,考察影响提取的主要因素,寻求最佳萃取工艺.超临界CO2萃取最佳工艺条件为:压力32MPa,温度32℃,CO2流量25kg/h,萃取时间80min,得率36.45%;微波萃取最佳工艺条件为:溶剂为正己烷,物料质量与溶剂质量比例1:3,辐射时间7min,辐射功率720w,得率27.12%.超声波萃取最佳工艺条件为:物料质量与溶剂质量比例1:7,溶剂为正己烷,浸泡时间18h,得率17.37%.结果表明超临界CO3萃取葵花子油品质最好,而且萃取也最高,质量最稳定.     

香草兰精油微胶囊的制备工艺优化及缓释性分析

以辛烯基琥珀酸淀粉钠和麦芽糊精为壁材,香草兰精油为芯材,通过喷雾干燥的方式制备香草兰精油微胶囊。5种单因素实验结果表明:壁芯比、均质压力、固形物质量分数对包埋产率具有显著影响。通过响应面实验设计得到最佳制备香草兰精油微胶囊的工艺条件为壁芯质量比4∶1、均值压力20 MPa、固形物质量分数40%,该条件下包埋产率为(97.21±0.3)%,包埋率为(89.16±1.2)%。100℃加热30 h后,微胶囊的挥发率为22.12%,结果表明微胶囊能够显著降低精油的挥发速率。     

香草兰生防细菌的筛选、分子鉴定及其抑菌机制的初步研究

通过平板对峙法从香草兰根际微生物中筛选出对香草兰根(茎)腐病菌(Fusarium oxysporum)、香草兰疫病菌(Phytophthora nicotianae)和香草兰细菌性软腐病菌(Erwinia carotovora)均有良好抑制效果的生防菌10株。通过16S rDNA序列比对及系统发育树分析,其中7株为解淀粉芽孢杆菌(Bacillus. amyloliquefaciens),2株为枯草芽孢杆菌(B. subtils),1株为甲基营养型芽孢杆菌(B. methylotrophicus)。提取脂肽类化合物进行抑菌分析,发现10株生防菌脂肽类提取物对香草兰根(茎)腐病菌和香草兰疫病菌均有良好的抑制效果,有4株的脂肽类粗提物对香草兰细菌性软腐病菌有强烈的抑制活性。对其中2个菌株脂肽类粗提物进行MALDI-TOF/TOF-MS检测,发现菌株 VX2R11 产生表面活性素(Surfactin)和伊枯草素A(IturinA)2种脂肽类化合物,菌株 VX2S02 仅产生伊枯草素A,推测产生伊枯草素A是菌株VX2R11和VX2S02拮抗香草兰根(茎)腐病菌和疫病菌重要机制;产生表面活性素是菌株VX2R11拮抗香草兰细菌性软腐病菌的重要机制。     

Characterization of O-β-glucosidase Activity in Vanilla planifolia and the change during the Curing Crocess of Vanilla Beans

香草兰是最重要的食品香料之一,其主要香味成分为香兰素,主要存在于香草兰豆荚中.香兰素一般由成熟豆荚中的香兰素葡萄糖苷经过漫长的发酵过程转化而来.O-β-葡萄糖苷酶在发酵生香的过程中起着关键作用.研究结果表明:香草兰的根、茎、叶和豆荚中都具有O-β-糖苷酶活性,豆荚活性最高,叶片活性最低；来自不同器官的O-β-糖苷酶的底物特异性一致,都能降解香兰素糖苷、2-NPG、4-NPG,都不能降解n-OG及硫代葡萄糖苷；香草兰糖苷酶提取物在50～60℃处理1 min,对酶活性影响很小,70℃处理1 min,酶活性丧失约40％,说明香草兰糖苷酶对高温具有一定耐受性,杀青后剩余糖苷酶活性在漫长的发酵过程中能够满足酶促反应的需求.     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.     

Recent Modifications of Chitosan for Adsorption Applications: A Critical and Systematic Review

Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase).