紫草不同溶剂提取物抑菌活性研究

采用滤纸片扩散法和混平板稀释法研究了紫草不同溶剂提取物的抑菌作用及温度对其抑菌活性的影响.结果表明,正丁醇、乙酸乙酯、石油醚、氯仿等四种溶剂提取物均具有较强的抑菌活性,对受试菌的MIC范围在1～2mg/mL之间.抑菌能力大小顺序为乙酸乙酯提取物≥正丁醇提取物＞石油醚提取物＞氯仿提取物.四种提取物对细菌的抑菌能力均大于真菌,且它们的抑菌活性具有较好的热稳定性.     

高效液相色谱法同时测定紫草素及其衍生物

建立了高效液相色谱法同时测定紫草中的紫草素、去氧紫草素、异丁酰基紫草素、β,β-二甲基丙烯酰基紫草素、异戊酰基紫草素和2-甲基正丁酰基紫草素等萘醌类衍生物含量的方法。该方法简便、快速、线性范围宽、适应性好,可用于对紫草药材及紫草提取物中的萘醌类衍生物的含量测定和质量控制。     

紫草抗氧化成分的提取及其活性测定

分别用石油醚、三氯甲烷、乙醇依次提取紫草成分，浓缩干燥后，用烘箱法及ＯＳＩ仪测定了３种提取物对油脂氧化稳定性的影响，发现石油醚提取成分和三氯甲烷取成分有明显的抗氧化活性。在猪油中，ＬＥ－ｐｅｔ比ＶＥ的抗氧化活性强，并且ＬＥ－ｐｅｔ与ＶＥ混合使用时两者具有抗氧化同协同增效作用。     

黄花软紫草地上部分有效成分分析及黄酮的测定

对黄花软紫草的地上部分采取不同的方法进行有效成分分析，如水提法、醇提法、石油醚提取法，结果是黄花软紫草中含有丰富的有效成分，然后采用乙醇回流浸提法对黄花软紫草的不同部位进行了黄酮的提取和测定，结果表明黄酮的含量顺序为花〉叶子〉茎。     

紫草色素超临界萃取与有机溶剂萃取之比较

本文对新疆紫草进行了超临界萃取工艺研究并与有机溶剂萃取的结果进行比较。结果表明:超临界萃取在32℃、压力27MPa下重量得率最高,达4.2%;紫草素衍生物也达最高,为3.59%。超临界萃取比有机溶剂萃取能得到更多紫草萘醌组分。超临界萃取的紫草色素含杂质更少。     

复方紫草抗氧化剂的毒性初步评价

以乙醇提取法获得紫草提取物(Z)和甘草提取物(G),以碱提酸沉法获得槐米提取物(H),再辅以柠檬酸(N)和VE(E),按Z:G:H:N:E 为10:5:5:2:1 的比例复配成复方紫草抗氧化剂(FZK)。以FZK 为受试物,通过小鼠经口急性毒性实验、小鼠骨髓细胞微核实验、小鼠骨髓细胞染色体畸变实验等毒理学实验对FZK 的毒性进行了评价。结果表明：小鼠经口最大耐受剂量均大于16000mg/kg bw,FZK 急性毒性分级为无毒级。剂量小于8000mg/kg bw 条件下,FZK 对小鼠嗜多染红细胞微核率无促提高作用,对小鼠骨髓细胞染色体无致畸作用。该食品添加剂不存在致突变性。     

新疆紫草不同部位不同溶剂提取物体外抑菌效果的研究

采用不同溶剂对新疆紫草的根和地上部分进行提取,利用纸片扩散法对大肠杆菌、金黄色葡萄球菌、八叠球菌、枯草芽孢杆菌、铜绿假单胞菌进行体外抑菌实验,研究不同溶剂提取物的抑菌能力,并测定其抑菌直径和最小抑菌浓度。结果表明,紫草根的乙醇提取物对上述5种细菌均有明显的抑菌作用,最小抑菌浓度分别为250、125、15.7、62.5、500 mg/mL;新疆紫草根水提取物、新疆紫草地上部分水提取物和醇提取物对上述5种病原菌均无明显抑制作用。     

紫草素提取及抗氧化性能研究

主要研究紫草素的提取工艺及其抗氧化性能,选用的提取工艺有碱提酸沉、醇提、高压脉冲提取,紫草素的性能表征主要通过它的抗氧化性能来研究.     

超声波-微波协同萃取紫草总色素及紫草素的制备

以新疆紫草为原料,乙醇作萃取剂,考察了超声波-微波协同萃取紫草总色素的工艺条件.并采用Cu2络合纯化方法将萃取所得的总色素水解制备成了紫草素.在超声波功率内置为50W的仪器条件下,采用分光光度法测定提取液吸光度的方法考察了萃取剂浓度,料液比,微波功率、提取时间对色素提取效果的影响.通过单因素实验和L9(34)正交实验确定了萃取紫草总色素的优化工艺条件为:乙醇浓度90％,料液比1:12,微波功率70W,提取时间7min.在此优化条件下紫草素及其衍生物的得率可达5.36％.总色素经Cu2络合纯化水解为紫草素的得率为29.25％.这是一种实验室中简单、快速、高收率的由天然紫草分离制备紫草素的有效方法.     

棉织物的天然紫草色素染色

研究了紫草色素的提取方法以及提取工艺对色素溶出量的影响,并对紫草在棉织物上的媒处理及染色工艺进行了试验。结果表明,采用100%乙醇提取紫草色素,提取浴比(紫草的质量/无水乙醇的质量)1∶20～1∶30,提取温度40～50℃,提取时间2～4h;采用硫酸铝钾前媒法处理棉织物,硫酸铝钾质量浓度5g/L,媒处理温度70℃,时间30min,pH值为3～4;优化的染色条件为:染色温度60℃,pH值4,时间30～50min,紫草染液可重复利用1～2次;染色织物干摩擦牢度4～5级,湿摩擦牢度3～4级,皂洗牢度4级。     

Encapsulation of food ingredients

Microencapsulation is a relatively new technology that is used for protection, stabilization, and slow release of food ingredients. The encapsulating or wall materials used generally consist of starch, starch derivatives, proteins, gums, lipids, or any combination of them. Methods of encapsulation of food ingredients include spraydrying, freeze‐drying, fluidized bed‐coating, extrusion, cocrystallization, molecular inclusion, and coacervation. This paper reviews techniques for preparation of microencapsulated food ingredients and choices of coating material. Characterization of microcapsules, mechanisms of controlled release, and efficiency of protection/ stabilization of encapsulated food ingredients are also presented.     

Depth of concussion in cattle shot by penetrating captive bolt

The prevalence of shallow depth of concussion following captive bolt shooting was assessed in 1608 cattle at an abattoir. Depth of concussion was determined in each animal from physical collapse, presence or absence of corneal reflex, normal rhythmic breathing, eyeball rotation, and whether the animal was re-shot. The presence of nystagmus and the absence of tongue protrusion were also monitored as potential indicators of a shallow depth of concussion, and simultaneous noise measurements assessed whether loudness of gun discharge was linked to concussion depth. The prevalence of a shallow depth of concussion was 8% for all cattle and 15% for young bulls. Nystagmus was associated with other indicators of a shallow depth of concussion. Absence of tongue protrusion was not associated with depth of concussion, but could serve as a useful indicator of jaw relaxation and insensibility following exsanguination. Soft-sounding shots (111 dB) when using 4.5 gr cartridges were associated with shallow depth of concussion.     

Water–disaccharides interactions in saturated solution and the crystallisation conditions

This paper reports solubility data and measurements of viscosity of the saturated aqueous solutions of sucrose, maltitol, and trehalose. Likewise, the metastable zone width and velocity of nucleation of the three disaccharides are compared. The narrowest metastable zone is observed for maltitol and the largest for trehalose. Such behaviour is due to a higher affinity of trehalose for water. Moreover, the crystallisation of anhydrous disaccharides in aqueous solution necessitates that hydration water be removed and evacuated from crystal integration surface to the bulk of solution to allow the growth of crystals. This step of disassociation and diffusion of hydration water proves to be the controlling step of the crystallisation process. Structural features at the origin of the differences between the three sugars are studied by FTIR spectroscopy. Modifications of frequencies and intensities of the vibrations around the glycosidic bond are interpreted in terms of conformational flexibility. Arguments like H-bond strength or conformational flexibility of the two monomers around the glycosidic oxygen were evoked as possible explanations of the behaviour of disaccharides. Likewise stability of hydration of the disaccharides is derived from the interpretation of FTIR spectra. These structural features help in interpreting the differences in crystallisation conditions and to hypothesize about the cryoprotective ability of the studied molecules.     

39—THE FLOW OF LIQUID FROM A JET THROUGH A COMPRESSIBLE POROUS LAYER. PART III: THE CHARACTERISTICS OF LIQUID FLOW THROUGH A COMPRESSIBLE LAYER OF LOOSE WOOL

The effects on the conditions of flow of the surface and configurational properties of the fibres in a compressible porous layer are discussed. The characteristics of a layer of wool are evaluated, and its compressibility is determined. It is shown that, when a liquid of initial uniform pressure flows through a compressible porous medium, the pressure gradient within the medium increases with the distance of flow. The resulting pressure drop is found to depend on a function of the ratio of the downstream to the upstream porosity of the compressible medium. Experimental results are reported for permeable flow through various layers of loose wool; these indicate that, when the flow is disturbed turbulent, the pressure drop through the layers is proportional to the square of the filter velocity. This result is not readily apparent from the graphs of pressure drop against filter velocity because of the compressibility of the fibres.     

Headspace solid‐phase microextraction analysis of artificial flavors

Using a non‐equilibrated solid‐phase microextraction/gas chromatography/mass spectrometry technique, differentiation between a wide variety of types and examples of artificial flavors has been demonstrated. Addition of an internal standard to the samples, as received, allowed for the calculation of yields on a µg g^?1 basis for the majority of headspace volatiles. The relative standard deviation values expressed as percentages were between 3 and 5%. The precise nature of the approach coupled with the compound identification capacity of the mass spectrometer afforded the capability to easily differentiate between multiple sources of artificial flavors. With a total analysis time of approximately 30 min and the absence of solvent, this approach has the capability of detecting and quantifying the presence of the low‐molecular‐weight solvents often used in the preparation of artificial flavors. Such a capability represents a distinct advantage over more conventional methods of solvent dilution. Results from conventional gas chromatography/mass selective detector analyses are contrasted and compared with the results obtained from the headspace SPME approach. Copyright © 2005 Society of Chemical Industry     

21—THE ACETYLATION OF COTTON

An account is given of a study of the effect of the amount of activating agent, the temperature, the catalyst, and the diluents used in the acetylation of cotton with perchloric acid as catalyst. Sulphuric acid was compared with perchloric acid as a catalyst. The effects of traces of water, the amount of acetyl chloride, and the rate of acetylation were studied in the acetylation of cotton with acetyl chloride and pyridine. The conditions in all cases were such that the acetylated cotton retained its fibrous form.     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Biodegradation of genetically modified seeds and plant tissues during composting

BACKGROUND: The increasing global market of genetically modified (GM) crops amplifies the potential for unintentional contamination of food and feed with GM plants. Methods proposed for disposal of crop residues should be assessed to prevent unintended distribution of GM materials. Composting of organic material is inexpensive and location‐independent. The objective of this study was to determine the effectiveness of composting for disposal of GM plants in terms of reducing seed viability and promoting the degradation of endogenous as well as transgenic DNA. RESULTS: Duplicate samples of corn kernels, alfalfa leaves, and GM canola seeds, meal and pellets were sealed in porous nylon bags and implanted in duplicate 85 000 kg (initial weight) feedlot manure compost piles. Samples were collected at intervals over 230 days of composing. Canola seeds and corn kernels were not viable after 14 days of composting with temperatures in the piles exceeding 50 °C. In all samples, PCR analyses revealed that plant endogenous and transgenic fragments were substantially degraded after 230 days of composting. Southern blotting of genomic DNA isolated from canola seeds identified differences in the persistence of endogenous, transgenic, and bacterial DNA. CONCLUSION: Composting GM and non‐GM plant materials with manure rendered seeds non‐viable, and resulted in substantial, although not complete, degradation of endogenous and transgenic plant DNA. This study demonstrates that composting could be effective for disposing of GM crops in the event of their inadvertent entry into the food or feed chain. Copyright © 2010 Crown in the right of Canada. Published by John Wiley & Sons, Ltd