共查询到20条相似文献,搜索用时 46 毫秒
1.
为了探究南瓜提取物中叶黄素酯的皂化工艺条件和其体外抗氧化能力,在单因素试验基础上,以皂化液浓度、皂化温度和皂化时间为响应因子,采用Box-Behnken中心组合实验原理进行三因素三水平设计,优化南瓜叶黄素的皂化工艺;利用高效液相色谱(HPLC)和质谱(MS)分析检测皂化产物;经硅胶柱色谱分离得到纯化的南瓜叶黄素;采用分光光度法,通过比较DPPH·和·OH的清除能力评价南瓜中游离叶黄素的体外抗氧化活性。结果表明,南瓜提取物中叶黄素酯的最佳皂化工艺条件为皂化液质量浓度33 g/dL,温度33 ℃,时间5.5 h。在最优工艺条件下,南瓜提取物中游离叶黄素得率为0.4175%,与预测值相近,说明该优化工艺稳定可行。高效液相色谱(HPLC)和质谱(MS)分析检测表明皂化产物为叶黄素。硅胶柱色谱纯化后,游离叶黄素的纯度可提高到91.39%。南瓜中游离叶黄素清除DPPH·和·OH的半抑制质量浓度IC50分别为0.021 4 mg/mL和0.038 3 mg/mL,抗氧化活性较高,可作为一种良好的天然抗氧化剂。 相似文献
2.
3.
4.
5.
6.
试验采用了超声波辅助KOH-碱溶液进行皂化工艺研究,以皂化碱液浓度、碱液加入量、皂化时间、皂化温度为自变量。通过响应面分析法,研究了各因素及其交互作用对万寿菊中叶黄素皂化反应的影响。结果表明:叶黄素皂化的最佳工艺条件为:KOH-碱溶液浓度11.35%、碱液加入量172.37mL、皂化温度51.55℃、皂化时间2.09h。叶黄素含量的预测值为15.53mg/g。当选取KOH-碱溶液浓度11%、碱液加入量170mL、皂化温度50℃、皂化时间2h的实际条件时,叶黄素的含量实际值达到15.64mg/g。 相似文献
7.
《中国食品添加剂》2018,(12)
以万寿菊油树脂为原料,采用源于宏基因组文库脂肪酶处理,有机溶剂萃取的方法提取叶黄素,研究优化此过程的工艺条件。实验表明:万寿菊油树脂的最适溶解介质为乙醇溶液,宏基因组文库脂肪酶的添加量为万寿菊油树脂的2.0%,水解时间为12min,水解温度为50℃,液料比7v/m,提取温度40℃。对此工艺进行验证叶黄素提取率可达94.8%,收率为84.6%;总类胡萝卜素的含量为87.2%,其中含全反式叶黄素91.2%,全反式玉米黄质5.6%。与普通酶法提取叶黄素的方法相比较,本研究所采用的宏基因文库脂肪酶的效率更高,制备的叶黄素含量和收率更高,此方法明显优于普通酶法。 相似文献
8.
试验采用了有机溶剂浸提和氢氧化钾甲醇溶液皂化的方法,研究了万寿菊叶黄素的提取与皂化的工艺条件.试验考察了提取剂种类、提取温度、提取时间、料液比对提取效果的影响,以及皂化液种类、皂化液浓度、皂化液用量、皂化温度、皂化时间、对皂化的影响.通过单因素试验确定的提取和皂化工艺条件为:提取剂为无水乙醇:石油醚(沸程为60℃~90℃)(2:1),料液比为1:100,提取温度45℃,提取时间80min,皂化液浓度20%,皂化液用量0.2mL,皂化温度40℃,皂化时间80min.选用乙醇—石油醚混合溶剂作为提取剂,具有价格便宜、低毒、沸点低、溶剂回收成本较低、生产安全性高等优点.该提取剂用于工业生产中提取叶黄素是可行的. 相似文献
9.
10.
万寿菊花中叶黄素酯的提取及皂化工艺 总被引:1,自引:0,他引:1
叶黄素具有调节人体的免疫能力、防治老年性视黄斑退化和白内障等作用,目前天然叶黄素的提取原料主要为万寿菊花,万寿菊花的有机溶剂提取物含有大量叶黄素酯,经皂化后可转变为叶黄素,广泛用于食品、食品添加剂、药品及饲料等工业.本文采用甲醇处理万寿菊鲜花后直接用正己烷提取叶黄素酯,并通过L9 (34)正交实验选择了叶黄素酯皂化的最佳条件,即KOH/甲醇浓度为20%,提取液﹕KOH为4 : 1,时间为40min,温度为50℃时,叶黄素酯皂化进行的比较完全.皂化得到的叶黄素在丙酮﹕甲醇(v : v)为1 : 1的混合溶剂中进行重结晶,得到叶黄素晶体,纯度为97.2%. 相似文献
11.
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. 相似文献
12.
John Gilbert Catherine Simoneau David Cote Achim Boenke 《Food Additives & Contaminants》2000,17(10):889-893
An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium. 相似文献
13.
Sophie Guillot Laurence Peytavi Sylvie Bureau Renaud Boulanger Jean-Paul Lepoutre Jean Crouzet Sabine Schorr-Galindo 《Food chemistry》2006
The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties. 相似文献
14.
Jesus Simal-Gandara Miguel Sarria-Vidal Arjen Koorevaar Rinus Rijk 《Food Additives & Contaminants》2000,17(8):703-711
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. 相似文献
15.
Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates 总被引:2,自引:0,他引:2
A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel. 相似文献
16.
17.
Yoko Uematsu Keiko Hirata Kumi Suzuki Kenji Iida Kazuo Saito 《Food Additives & Contaminants》2001,18(2):177-185
BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H2O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol. 相似文献
18.
Anne Theobald Catherine Simoneau Philippe Hannaert Patrizia Roncari Anna Roncari Thomas Rudolph Elke Anklam 《Food Additives & Contaminants》2000,17(10):881-887
The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study. 相似文献
19.
A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years. 相似文献
20.
M. S. Garcí a-Falc n J. Simal-G ndara S. T. Carril-Gonz lez-Barros 《Food Additives & Contaminants》2000,17(12):957-964
A simple, rapid and inexpensive method has been developed for the determination of benzo[a 相似文献