乳脂中1,3-甘油二酯检测方法的研究

建立一种乳脂中1,3-甘油二酯(1,3-DG)定性定量的检测方法.通过薄层色谱法(TLC)对乳脂中1,3-甘油二酯进行分离和定性,再用甘油氧化酶法进行定量检测.研究结果显示:薄层色谱法能有效分离出1,3-甘油二酯;定量方法RSD小于等于3.78%,回收率在86.73%～101.83%之间.该方法能准确、快速、灵敏地分离检测乳脂中的1,3-甘油二酯.     

水活度对全细胞脂肪酶GZUF36催化合成1,3-甘油二酯中的影响

1,3-甘油二酯是一种健康油脂,并且可用来合成药物的中间材料,但其在天然油脂中含量有限。所以本文用黑曲霉GZUF36全细胞脂肪酶法甘油解合成了1,3-甘油二酯,重点探讨了影响其合成的关键因素:水活度。控制水活度的方法包括用饱和盐溶液平衡酶粉、水合盐平衡反应体介质、水合盐控制水活度水合盐分别预平衡酶粉和反应介质。结果表明,水活度显著地影响1,3-甘油二酯的产量和脂肪酶对1,3-甘油二酯的选择性。过高或过低的水活度都不利于全细胞脂肪酶GZUF36催化甘油解反应合成1,3-甘油二酯,水活度过低会导致酶活力不高,水活度过高则易使催化反应向水解方向进行。当用aw=0.58的水合盐分别预平衡酶粉和反应介质时,1,3-甘油二酯的得率和脂肪酶对1.3-甘油二酯的选择性都为最优,分别是26.100%和83.056%。本文为进一步优化全细胞脂肪酶GZUF36催化的选择性合成1,3-甘油二酯中的反应体系奠定了基础。     

甘油二酯的合成、代谢及应用研究进展

甘油二酯是油脂代谢的中间产物,是一种重要的功能油脂,也是国际公认安全的食品成分。根据脂肪酸酰基与甘油骨架上羟基连接位置不同,甘油二酯分为1,3-甘油二酯、1,2-甘油二酯和2,3-甘油二酯三种异构体,其中1,2-甘油二酯和2,3-甘油二酯互为同分异构体。目前国内外多项研究表明甘油二酯特别是1,3-甘油二酯具有抑制脂肪积累和降低血脂的功能。因此,甘油二酯已被广泛应用于医药、食品、化工等工业领域中,具有良好的商业价值。本文主要介绍了甘油二酯的代谢、合成、检测、应用现状及伴随产生的食用安全性,并讨论了甘油二酯未来的研究方向。     

延黄牛脂制备高纯度1,3-甘油二酯工艺

目的:提高延黄牛脂的附加值。方法:采用固定化脂肪酶Lipozyme RM IM为催化剂,牛油脂肪酸乙酯(乙醇解法自制)和甘油为原料制备1,3-甘油二酯,运用氢谱考察脂肪酶添加量、底物摩尔比、反应时间以及反应温度对粗反应混合物中1,3-甘油二酯含量的影响,并阐明醇解酯交换前后牛油与甘油二酯产物的脂肪酸组成变化。结果:1,3-甘油二酯合成最佳条件为脂肪酶Lipozyme RM IM质量分数为1%,底物摩尔比(n_{脂肪酸乙酯}∶n_甘油)2∶1,反应时间6 h,反应温度50℃。此条件下的1,3-甘油二酯生成率为72.5%,甘油酯得率为77%;纯化后纯度提高至90.79%。与原油(延黄牛脂)相比,甘油二酯产物中亚油酸和油酸含量分别升高了13.65%,6.47%,饱和度降低了7.17%。结论:延黄牛脂制备1,3-甘油二酯不仅能改变甘油酯结构,还可以改变牛脂的脂肪酸组成,降低其饱和度。     

4种主要茶黄素单体分离制备方法研究进展

茶黄素是一类具有广泛开发前景的茶叶天然产物。本文综述国内外4 种主要茶黄素单体分离制备方法研究进展,比较分析纤维素层析法、葡聚糖凝胶层析法、硅胶层析法、高速逆流色谱法和聚酰胺层析法等茶黄素单体分离制备方法的优缺点,认为聚酰胺层析法是目前比较理想的4 种主要茶黄素单体分离制备方法,可为开发利用茶黄素提供一定的科学借鉴依据。     

橄榄油甘油二酯异构体的HPLC-ELSD测定方法建立及其应用

目的:建立一种用于测定橄榄油中甘油二酯异构体的方法,并应用于评价橄榄油的新鲜度。方法:采用正相高效液相色谱法,以异丙醇-正己烷为流动相进行梯度洗脱,应用蒸发光散射检测器进行检测。结果:1,3-甘油二酯(1,3-DAG)和1,2-甘油二酯(1,2-DAG)在20 min内实现分离,分别在11.16～111.62 μg/mL和9.50～95.00 μg/mL范围内线性关系良好,平均回收率分别为103.2%和101.4%,重复性及日间精密度RSD均低于4.0%;应用该方法测定了6批特级橄榄油的甘油二酯异构体含量,测定结果与橄榄油氧化情况相关性较好。结论:该方法能够准确、快速地测定橄榄油甘油二酯异构体的含量。     

吸附法提高1,3-丙二醇纯度的研究

1,3-丙二醇(英文名1,3-propanediol)是一种重要的化工原料,可作为有机溶剂应用于油墨、印染、涂料、润滑剂、抗冻剂等行业,还可用作药物合成中间体。其最主要的用途是作为聚合物单体合成性能优异的高分子材料。目前,1,3-丙二醇的生产方法主要有化学合成法和微生物发酵法两种。化学合成法主要为环氧乙烷经氢甲酰化再加氢法(EO法)和丙烯醛水合法(Acrolein法)。化学合成法的缺点是成本高、副产物多、选择性差、操作条件需高温高压、所利用的化学原料均为不可再生的石油或煤炭资源,且环氧乙烷和丙烯醛均属易燃易爆的危险品。生物发酵法生产1,3-丙二醇是近些年来国内外研究的重点,而且生物发酵法因其选择性高、操作条件温和、原料是可再生的农产品——淀粉或植物油料等优点,近年来受到了世界各国科学家的特别重视。在发酵法生产1,3-丙二醇的提取过程中,最终分离提纯的方法多为精馏操作。在实际生产过程中,精馏后的成品时常出现纯度不高且产品带有有颜色和气味的现象,经对该产品进行多次精馏提纯,产品质量有所改善,但因能耗过高,导致产品成本很高。摸索工艺简单、成本较低的二次提纯方法--吸附法是本研究重点。     

花椒麻味物质分子印迹分离的模板分子制备及鉴定

采用索氏抽提法、逆流干柱层析法及制备型高效液相色谱法等对花椒中的麻味物质进行分离纯化,再通过紫外光谱法、气质联用法、液质联用法和核磁共振谱法对分离的组分样品C作鉴定。研究结果表明:依次通过索氏抽提法、逆流干柱层析法及制备型高效液相色谱法可将花椒中麻味物质相对含量提高至97.71%(结晶体C样品),纯度很高。通过紫外光谱法、GC-MS法、LC-MS法和核磁共振法的检测,确定该物质为羟基-β-山椒素。通过感官确定其具有极强的麻味。样品C可作为花椒麻味物质分子印迹分离的模板分子。     

硅胶柱色谱制备高纯1,3-二油酸甘油二酯的研究

以实验室自制1,3-二油酸甘油二酯粗品(含量76.41%)为原料,采用硅胶柱色谱法制备高纯1,3-二油酸甘油二酯。通过硅胶薄层色谱对4种混合溶剂洗脱剂进行筛选,确定硅胶柱色谱最佳洗脱剂为D(正己烷-乙酸乙酯-乙醚-乙酸的混合液)。以1,3-二油酸甘油二酯的回收率和纯度为指标,系统考察了硅胶柱色谱的洗脱流速、上样质量浓度、硅胶量对纯化效果的影响,确定最佳硅胶柱色谱纯化条件为:洗脱流速1.5 m L/min,上样质量浓度75 mg/m L(上样体积10 m L),硅胶量30 g。该条件下制得的1,3-二油酸甘油二酯样品纯度达98.03%,回收率为69.90%。     

玉米赤霉烯酮替代物2,4-二羟基苯甲酸环十二烷酯的合成与应用（网络首发、推荐阅读）

2,4-二羟基苯甲酸环十二烷酯（CDHB）是一种与玉米赤霉烯酮在大小、形状、立体构象以及功能性上十分相似的一种化合物,可作为玉米赤霉烯酮（ZEN）的模板分子,用于制备分子印迹聚合物。在反应底物中加入N,N′-羰基二咪唑（CDI）作为活化剂、1,8-二氮杂双环[5.4.0]十一碳-7-烯（DBU）作为催化剂研究制备CDHB,并比较分析柱层析法、高速逆流色谱法和制备液相法3种不同纯化手段,进一步通过FTIR,UV-Vis,1H NMR,13C NMR和MS (ESI)确证CDHB结构,以分子印迹聚合物为例介绍CDHB的应用。结果表明,制备液相法获得的产品纯度最高（≥98%）,高速逆流色谱法次之,根据不同生产需求,3种纯化方法均可用于CDHB系统化制备过程;确证CDHB结构证实CDHB合成方法的重复性和稳定性,最终产率可达70%以上。将CDHB引入石墨烯载体上,提高分子印迹聚合物对ZEN的选择吸附能力,其吸附动力学遵循准二级动力学模型。     

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.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.