响应面法优化金银花多酚氧化酶提取工艺

以金银花为原料,采用匀浆浸提法提取多酚氧化酶,利用单因素试验和响应面优化法对料液比、提取pH值、聚乙烯吡咯烷酮（polyvinylpyrrolidone,PVP）添加量和浸提时间等工艺条件进行分析与优化。结果表明：匀浆浸提工艺参数对金银花多酚氧化酶提取有显著影响,影响显著顺序为缓冲液pH值＞料液比＞浸提时间＞PVP添加量。金银花多酚氧化酶匀浆浸提优化工艺参数：料液比1∶6.29（m/V）、缓冲液pH 8.03、PVP添加量1 g/100 mL、浸提时间1.71 h,在此条件下获得酶比活力为667.564 U/mg,所得多酚氧化酶提取回归模型显著（R2=0.9425）,拟合性好,可用于预测多酚氧化酶的提取效果。     

不同对虾中多酚氧化酶的提取比较及在虾体的分布研究

用丙酮法和匀浆浸提法分别对南美白对虾和中华管鞭虾进行多酚氧化酶的提取,结果表明,在同样的提取条件下,中华管鞭虾的酶活大于南美白对虾,匀浆浸提法提取的酶活比丙酮法高1.5倍;同时对中华管鞭虾的提取条件料液比、缓冲液pH、浸提时间、水浴温度做了研究,通过正交实验得到当料液比1∶4,缓冲液pH8,浸提时间3h,水浴温度45℃条件下提取的酶具有最大的活性;进一步研究中华管鞭虾的多酚氧化酶在虾体中的分布情况,得出虾头部位多酚氧化酶含量较高,虾尾和虾身含量较低。     

响应面法优化无核白葡萄多酚氧化酶的提取工艺

为了优化无核白葡萄多酚氧化酶的提取工艺。采用丙酮提取法、超声波辅助浸提法和缓冲溶液浸提法分别提取无核白葡萄多酚氧化酶,在单因素实验料液比、提取时间和缓冲液pH的基础上,利用响应面法优化无核白葡萄多酚氧化酶提取条件。结果表明,多酚氧化酶提取的最佳工艺为料液比1:1.8 (g/mL),浸提时间2.9 h,缓冲液pH5.8,无核白葡萄多酚氧化酶比活力为(378.12±1.3) U/mg,与模型预测值非常接近,拟合性好。采用响应面法分析,能较为准确的预测实验结果,以期为无核白葡萄多酚氧化酶纯化、性质、结构研究提供基础。     

超声波辅助提取茶鲜叶中茶多糖实验研究

本文研究了超声波辅助法提取茶树鲜叶中多糖的工艺。通过正交试验设计L9（3^4）提取多糖,以蒽酮-硫酸法测定多糖含量,得出优化工艺的条件为：固液比为1：10,浸提时间为60min、浸提温度为70℃、提取次数为3次,在此条件下茶粗多糖提取率为5．155％。     

响应面优化闪式提取香蕉多酚氧化酶

利用闪式提取方法,以香蕉多酚氧化酶的比活力为响应值,首先通过单因素试验考察多酚氧化酶提取缓冲液的种类、离子强度、pH值、液料比、提取时间、聚乙烯吡咯烷酮(PVPP)、聚乙二醇辛基苯基醚(Triton X-100)等因素对香蕉多酚氧化酶提取的影响,初步优化提取条件;进而通过Box-Behnken试验设计和响应面分析法综合优化最终提取条件。得出香蕉多酚氧化酶的理论最佳提取条件为:以磷酸-柠檬酸缓冲液、pH5.58、液料比1.57:1、PVPP质量浓度1.13g/100mL为提取液,用闪式提取器提取2.5 min。     

超声波、微波复合提取海带多酚的工艺研究

以超声波、微波复合浸提为前处理手段,在单因素实验的基础上采用正交实验对海带多酚浸提工艺参数进行了研究,确立了多酚提取工艺条件。结果表明:采用料液比(匀浆:乙醇,g/mL)1:7,乙醇体积分数85%,浸提温度70℃,浸提次数2次,浸提时间4h,提取效果最佳,海带多酚提取率为2.08%。     

响应面优化可溶态和膜结合态马铃薯多酚氧化酶提取工艺

以大西洋马铃薯为原料,分别用柠檬酸-磷酸盐缓冲液浸提和超声波辅助Tris-HCl缓冲液浸提法提取马铃薯中可溶态(sPPO)和膜结合态(mPPO)多酚氧化酶,以酶比活力为评价指标,在单因素实验基础上,通过响应面对sPPO和mPPO的提取工艺进行优化。结果显示:sPPO最优提取工艺为料液比1:3.2、浸提时间12 h、缓冲液pH7.1,在该条件下测定sPPO比活力平均值为(130.5±2.4) U/mg,三个因素对sPPO提取的影响大小依次为:浸提时间>料液比>缓冲液pH。mPPO最优提取工艺为料液比1:5.2、浸提时间7 h、缓冲液pH6.7,在该条件下测定mPPO比活力平均值为(686.4±7.9) U/mg,三个因素对mPPO提取的影响大小依次为:超声时间>料液比>缓冲液pH。所得响应面模型可以很好地预测和分析sPPO和mPPO提取工艺条件。     

滁菊活性成分的低温浸提及其对α-葡萄糖苷酶活性的抑制作用

为优化滁菊活性成分低温浸提工艺,以滁菊总多酚及总黄酮提取率为指标,考察时间、温度、液固比等因素对提取效果的影响,并采用正交实验优化浸提工艺 结果表明,滁菊低温浸提最佳工艺条件为:提取温度为60℃、液固比为30:1、浸提时间为50min,在此条件下,总多酚及总黄酮提取率分别为5.905、53.138mg/g滁菊浸提液对α-葡萄糖苷酶活性具有抑制作用,IC50为32μg/mL.     

海带多酚制备及其对南美白对虾保鲜效果的研究

采用超声渡、微渡复合浸提的方法预处理海带,制备具有抗菌活性的海带多酚.选取五因素(料液比、乙醇浓度、浸提温度、浸提次数、浸提时间)四水平的正交实验,以海带多酚提取率为评价标准,对海带多酚的提取工艺进行优化,并初步分析了海带多酚对南美白对虾的保鲜效果.结果表明:料液比1:7(匀浆:乙醇),乙醇浓度85%,浸提温度70℃,浸提次数2次,浸提时间4h为最佳提取工艺条件,其提取率可达0.4050%.0.2g/L的海带多酚可有效地延缓南美白对虾pH的升高,抑制其细菌总数和TVB-N值的增加,保持较好的感官质量.与对照组相比,应用海带多酚可延长南美白对虾货架期48h,使其保鲜期达到144h以上(-1.2±0.2℃).     

荔枝果肉多酚氧化酶提取与初步纯化

酶促褐变是影响荔枝果肉加工和贮藏的重要问题,多酚氧化酶(PPO)是引起酶促褐变的重要酶类.用磷酸缓冲液匀浆提取荔枝果肉中的多酚氧化酶,提取液最佳离子浓度为0.1mol/L、最适pH为7.5、最佳提取时间为2h,最适料液比为1:3.并通过硫酸铵沉淀和Phenyl Sepharowe CL-4B(苯基琼脂糖CL-4B)疏水柱层析进行初步纯化,该酶被纯化了9.4倍,得率为48%.     

Esters of para-aminobenzoic acid in cosmetics. Identification and dosage within sun-creams

A method is presented for the identification and determination by T.L.C. and G.L.C. of esters of para-aminobenzoic acid with a free amine function and of local anaesthetics, prohibited in cosmetic products, in accordance with the cosmetic directive 76/768/EEC. In a commercial product, nominally supplied as para-aminobenzoic monoglyceryl ester (authorised in sun-creams in accordance with the EEC directive) other phenyl groups with para substitution were identified by means of T.L.C. and N.M.R. spectroscopy; among them, the para-aminobenzoic ethyl ester. G.L.C. enables a quantitative determination of these substances. Les esters de l'acide para-amino benzoique dans les produits cosmétiques. Identification et dosage dans les crémes solaires     

argR基因对钝齿棒杆菌发酵过程中产精氨酸特性的影响

本文测定了一株钝齿棒杆菌（Corynebacterium crenatum）诱变菌和二株基因工程菌发酵过程中产arginine曲线、生长曲线以及发酵液中碳源消耗量和pH值的变化。实验结果显示Arg产量最高的菌株为C．crenatumA．S．M2.sp，其产量达到9mg／ml，据此认为钝齿棒杆菌中的argR基因可能为Arg代谢中的一个正调控因子。     

The distribution of anthocyanins in grape skin extracts of port wine cultivars as determined by high performance liquid chromatography

The distribution of anthocyanins in methanolic skin extracts of 16 grape cultivars used for port wine production and grown at five sites in the Douro Valley in Northern Portugal has been assessed by high performance liquid chromatography. Results are confined to the seven most readily separated and identified anthocyanins and are expressed as percentages of their total (88–99% of the total integrated area). Anthocyanins based on malvidin (Mv) predominated. Of these, Mv 3-glucoside was the major pigment (33–60%), being exceeded by Mv 3-p-coumarylglucoside (2–51%) in only two cultivars; Mv 3-acetylglucoside (1–15%) was consistently the lowest. Peonidin 3-glucoside (1–27%) was prominent in four cultivars, but delphinidin 3-glucoside (1–11%), petunidin 3-glucoside (2–11%) and cyanidin 3-glucoside (trace-6%) were of low proportions throughout. The ratio Mv 3-acetylglucoside/total Mv glucosides appeared characteristic of cultivar, independent of site, and a useful aid to identification of grape cultivars. The coloured pulp of some cultivars contained peonidin 3-glucoside as a major component, present in greater proportions than in the skin; the percentage of Mv 3-p-coumarylglucoside was lower in pulp than in skin. The identities of six of the seven anthocyanins were confirmed by fast atom bombardment mass spectrometry and the structures of the Mv derivatives were determined by nuclear magnetic resonance. The formation of formyl and acetyl anthocyanin artefacts is described.     

The saponin content and sapogenol composition of the seed of 13 varieties of legume

The total saponin content of various legume seeds together with their sapogenol composition have been determined. Extraction of the defatted flours was effected with methanol and subsequent acid hydrolysis yielded the soyasapogenols which were analysed using gas and thin-layer chromatography. The saponin levels ranged from 0–0.65% for defatted seed while the major sapogenol present in these saponins was soyasapogenol B. The figures obtained are compared with those previously reported and reasons are suggested for the discrepancies.     

The determination of bitter principles in zucchinis

A method using reverse phase thin layer and high performance liquid chromatography was developed to determine the level of the bitter principle occasionally found in zucchini (Cucurbita pepo L.). The system gave excellent separation with recovery rates of about 90% from spiked fruit. The bitter principle was confirmed by C¹³ NMR and mass spectrometry as cucurbitacin E glycoside which was present in concentrations in the order of 600mg kg^?1 in bitter fruits. Bitterness was detected by a taste panel at cucurbitacin E glycoside concentrations of 1 mg kg^?1 in aqueous solutions and 2 mg kg^?1 in zucchini pulp. The method described should assist the screening for bitterness in commercial and breeding populations of zucchini.     

设施栽培条件下葡萄光合特性初探

利用电子光合测定仪，对设施栽培条件下“乍娜”、“凤凰５１”品种的光合特性进行研究，结果表明葡萄光合日变化呈明显的双峰型，两品种光合峰值及光合低谷期长短有明显不同。在华北地区，影响设施内葡萄光合效率的主要生态因素是ＣＯ２浓度和水分状况，尤其是设施内相对湿度和光合效率有明显相关。     

利用SDS-PAGE电泳对啤酒生产过程中蛋白质动态变化的研究

采用SDS -PAGE电泳,对青岛啤酒酿造过程中的可溶性蛋白质变化进行了动态的跟踪。发现制麦和糖化过程是蛋白变化最明显的阶段,蛋白的分布和含量整体呈下降趋势。啤酒和啤酒泡沫中蛋白的分布较接近,主要表现为4 .3万的窄带和0 .7- 1.4万的宽带电泳图谱分布。     

Wine phenolics—analysis of low molecular weight components by high performance liquid chromatography

Low molecular weight phenolic compounds were separated by high performance liquid chromatography on hydrocarbon-bonded reverse phase packings, with a water-methanol elution gradient. Phenolic compounds were extracted from wine with ethyl acetate. A first extraction at pH 7 enabled isolation of neutral molecules (catechins, procyanidins, flavonols, aromatic alcohols); a second extraction at pH 2 was performed to extract phenolic acids. Successive injections of these two extracts in the chromatograph gave the distribution of the different phenolic compounds in the wine under analysis. Analytical data are given for low molecular weight phenolic compounds present in young red Bordeaux wines from different vine cultivars.     

Presence of quercetin-3-O-glucuronoside in Spanish table wines

Quercetin-3-O-glucuronoside has been identified in several Spanish table wines by thin-layer (t.l.c.) and high-performance liquid (h.p.l.c.) chromatographic methods. This is thought to be the first report of its occurrence in wine.