Influence of operation variables on quality parameters of olive husk oil extracted with CO<Subscript>2</Subscript>: Three-step sequential extraction

Supercritical CO₂ extraction is a viable alternative process for the extraction of high-quality oil from olive husk (also known as olive pomace), a residue obtained in the production of olive oil. We analyzed the effect of pressure (100–300 bar), temperature (40–60°C), solvent flow (1–1.5 L/min), and particle size (0.30–0.55 mm) on four important quality parameters of the oil extracted with CO₂: tocopherol concentration, extinction coefficients at 232 and 270 nm, and saponification value. Response surface methodology was used to obtain mathematical expressions related to the operating variables and parameters studied. Results from these experiments were also used to design a three-step sequential CO₂ extraction procedure to obtain a higher-quality extract. The optimal operational sequence consisted of a first extraction step at 75 bar for 1 h using 1% (vol/vol) ethanol modifier, followed by a second extraction stage at 350 bar for 2.5 h without ethanol and a third step, also at 350 bar, for 2.5 h but using ethanol. These extraction conditions obtained an intermediate fraction of oil with 64% yield and all normal parameters according to European Commission food legislation. This fraction is suitable without any further refining. On the contrary, the oils obtained by hexane extraction and by conventional supercritical CO₂ extraction at optimal conditions are suitable for human consumption after further refining. This last finding may result in improved economics of the sequential CO₂ extraction process compared to the conventional extraction method with hexane.     

分光光度法测脱硫溶液中栲胶、“888”含量

用分光光度法同时测定脱硫溶液中栲胶和“888”含量,结果表明,吸收波长分别为450nm和650nm,栲胶、“888”在使用浓度范围内,符合线性关系。该方法操作简易,结果准确。     

Orientation ofMicroplitis croceipes (Hymenoptera: Braconidae) to green leaf volatiles: Dose-response curves

FemaleMicroplitis croceipes wasps were tested in a wind tunnel for their ability to orient to various concentrations of eight different green leaf volatile (GLV) substances [hexanal, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-3-hexen-1-ol, (E)-2-hexenyl acetate, (Z)-3-hexenyl acetate, (Z)-3-hexenyl propionate, and (Z)-3-hexenyl butyrate]. Overall, the esters elicited the greatest percentage of successful orientation flights, the alcohols elicited an intermediate response, and the aldehydes elicited a low response. The semilog dose-response curves were generally hill-shaped with high responses at medium release rates and low responses at high or low release rates. For the aldehydes, positive responses occurred at all GLV release rates between 0.01 and 100 nl/min. For some alcohols and esters, positive responses occurred at release rates as low as 1 pl/min and as high as 1μl/min. These data show thatM. croceipes wasps are strongly attracted to GLVs and are capable of orienting to GLV concentrations that would occur in nature when a caterpillar feeds on a green leaf. Hence, in nature, GLVs may be important clues, enablingM. croceipes to locate their hosts.     

Physical properties and morphology of polycaprolactone/starch/pine‐leaf composites

Polycaprolactone (PCL)/starch and PCL/starch/pine‐leaf composites, which can be possibly applied as biodegradable food packaging materials with natural pine flavor, were prepared and characterized in this study. The effect of incorporating a silane coupling agent at different content levels on the physical properties and morphology of the composites was studied. To investigate the melting behavior of the composites, a differential scanning calorimetry was employed. A universal testing machine was used to investigate the tensile properties of the composites and the water absorption properties of the composites were also investigated. Scanning electron microscope was used to investigate the morphology of the composites. The physical properties and morphology of the PCL/starch and PCL/starch/pine‐leaf composites were largely affected by the composition, especially the content of the silane coupling agent. The silane coupling agent led to a much better interfacial compatibility between the PCL matrix and the fillers and resulted in better physical properties of the composites. The PCL/starch/pine‐leaf composite with the silane coupling agent showed a morphology, indicating a good interfacial adhesion between the PCL matrix and the fillers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 928–934, 2007     

东北红豆杉中紫杉醇的含量分析

以抗癌活性成分紫杉醇作为标准物,利用高压液相色谱法分析了东北红豆杉树叶和树干的水提取物中抗癌活性成分紫杉醇的含量,确定最佳色谱条件为：色谱柱：C18,Φ4.6×250 mm;流动相：甲醇︰水︰乙腈=45︰35︰20;检测波长：225 nm;柱温：室温;流速：1.0 mL/min。结果表明：东北红豆杉树干中紫杉醇含量高于树叶。     

茶皂素及其在化妆品中的应用

概述了茶皂素的来源、提取工艺、结构和特性,主要介绍了茶皂素在化妆品中的应用．作为基质成分,茶皂素可以用于洗发香波、天然草本洗发露、防晒消炎润肤膏、沐浴液等,它不仅具有良好的乳化、发泡、分散、渗透、润滑等活性作用,而且还具有消炎、镇痛、杀菌、止痒等药理作用．同时介绍了茶皂素在化妆品及纺织品洗涤、医药和农药等方面的应用前景．     

马铃薯叶片外植体再生系统的建立

选用马铃薯的叶片作为外植体,MS为基本培养基,采用不同浓度组合的BA和NAA对马铃薯再生系统的影响进行了研究.结果表明：最佳培养基为MS＋1.5 mg/L BA＋0.3 mg/L NAA,分化率为75%.采用该培养基研究了不同着生位置的叶片、同一着生位置叶片的不同切断以及叶片在培养基上的放置方式对马铃薯叶片再生的影响.结果表明：带有叶柄的下切断比其余叶片切断不定芽再生率高,幼嫩叶片比老化叶片再生率高.叶片再生系统的建立为马铃薯的遗传转化和工厂化育苗奠定了基础.     

五倍子醇提物的抗氧化活性

从还原力、清除DPPH自由基、清除超氧阴离子、清除羟自由基和抗脂质过氧化作用等方面研究了五倍子乙醇提取物的抗氧化活性,并同Vc或VE进行比较.实验结果表明,五倍子提取物对以上测定方法均表现出明显的抗氧化活性,其抗氧化活性均随其浓度的增加而增强.五倍子提取物和Vc(或VE)在同等浓度下,五倍子提取物的还原力和清除超氧阴离...     

天然染料银杏叶上染棉织物的媒染工艺研究

对棉织物进行银杏叶天然染料媒染染色,同时考察银杏叶媒染后织物的色牢度.探讨了明矾、硫酸铜两种媒染剂对棉织物银杏叶染色性能的影响;通过正交设计试验,确定了媒染最佳工艺条件.试验结果表明,明矾媒染最佳工艺为染色温度70℃、媒染时间25 min、媒染剂质量浓度10 g/L;硫酸铜媒染最佳工艺为染色温度60℃、媒染时间25 m...     

Inhibition and recovery of cucumber roots given multiple treatments of ferulic acid in nutrient culture

Ferulic acid, a frequently cited allelopathic agent, inhibited photosynthesis, leaf expansion, and root elongation of cucumber seedlings grown in aerated nutrient cultures in a growth chamber. Other effects were a reduction in the proportion of radioactivity fixed by photosynthesis translocated to roots, a stimulation in secondary root initiation, and an increase in root-shoot ratios. Inhibition of leaf expansion and root elongation induced by multiple ferulic acid treatments was rapidly lost once ferulic acid was removed from the root environment. The changes in general root morphology, i.e., average root length and root number, associated with ferulic acid treatments, were partially reversed or not affected when ferulic acid was removed from the root environment.Paper No. 11411 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina 27695-7601. The use of trade names in this publication does not imply endorsement by the North Carolina Agricultural Research Service of the products named, nor criticism of similar ones not mentioned.