磷脂酶Lecitase Ultra和磷脂酶C复合对冷榨菜籽油脱胶的影响北大核心CSCD

为了提高脱胶效率,以冷榨菜籽原油为原料,磷脂含量为指标,采用磷脂酶Lecitase Ultra和磷脂酶C复合酶法对冷榨菜籽油进行脱胶。采用单因素试验考察磷脂酶Lecitase Ultra反应时间、磷脂酶C反应时间、加水量、磷脂酶Lecitase Ultra添加量、磷脂酶C添加量、柠檬酸溶液添加量对脱胶油磷脂含量的影响,并通过响应面法优化脱胶条件。对优化的脱胶条件下所得到的脱胶油的理化指标进行了检测,并与国标一级压榨菜籽油进行了比较。结果表明:磷脂酶Lecitase Ultra和磷脂酶C对冷榨菜籽油进行酶法脱胶的最佳工艺条件为磷脂酶Lecitase Ultra添加量33 mg/kg,磷酯酶Lectase Ultra反应时间90 min,磷脂酶C添加量65 mg/kg,磷脂酶C反应时间60 min,加水量33 mL/kg,柠檬酸溶液添加量1.2 mL/kg;在优化条件下脱胶,脱胶油中磷脂含量为2.3 mg/kg,脱胶油的过氧化值和酸值均达到一级压榨菜籽油的国家标准。综上,磷脂酶Lecitase Ultra和磷脂酶C复合脱胶效果较好,所优化的工艺条件可用于菜籽油的脱胶。     

酶法脱胶在浓香菜籽油上的应用

以浓香菜籽毛油为原料,分别采用Purifine~?PLA1、Purifine~?PLC及Purifine~?3G 3种磷脂酶和传统水化法进行脱胶,并对油脂得率、脱胶浓香菜籽油质量和风味等进行系统评价。结果表明,在油脂得率方面,上述3种磷脂酶脱胶较传统水化脱胶均有显著性提升,采用离心法分别可以提升0.47%、0.31%、0.52%,采用自然沉降法分别可以提升4.32%、2.95%、5.77%。在质量方面,3种磷脂酶脱胶和传统水化脱胶均可将浓香菜籽油的含磷量降至20 mg/kg以内,且对脱胶浓香菜籽油的过氧化值、色值、加热试验和冷冻试验等均无显著影响;Purifine~?PLC和Purifine~?3G对脱胶浓香菜籽油酸价无显著影响,Purifine~?PLA1可导致酸价的显著上升;3种磷脂酶脱胶浓香菜籽油与传统水化脱胶浓香菜籽油的酸价和过氧化值在储藏期间变化趋势一致。在风味方面,3种酶法脱胶浓香菜籽油与传统水化脱胶浓香菜籽油在储藏14 d后呈现出差异。消费者喜好度分析结果表明,3种磷脂酶脱胶浓香菜籽油的风味均优于传统水化脱胶浓香菜籽油。     

菜籽油酶法脱胶的研究

研究磷脂酶对菜籽油脱胶及品质的影响,通过单因素、正交试验并结合生产成本确定最佳工艺条件。结果表明最佳工艺参数为:酸碱比(V/V)1:4.5,加酶量88 mg/kg,反应温度50℃,反应时间4 h。在此条件下,菜籽油的磷含量可由原来的406.66 mg/kg降到3.42 mg/kg;采用棒状薄层色谱—氢火焰离子化检测器测菜籽毛油与脱胶油的甘油酯含量,脱胶油的甘油酯中甘一酯的含量变化不太明显,甘二酯的质量分数从毛油的2.50%增加到6.51%,而甘三酯的质量分数从96.08%降到90.46%。Rancimat法测定氧化稳定性后发现,脱胶油的氧化诱导时间由毛油的5.37 h增加到6.10 h,表明酶法脱胶后的菜籽油的氧化稳定性高于菜籽毛油;同时对水化脱胶磷脂与酶法脱胶磷脂中的溶血磷脂进行对比分析,其质量分数分别为10.71%和65.76%,酶法脱胶的酶解率达65.72%。     

磁性固定化PLA_1的制备及其在脱胶应用中的研究

本文目的是研究磷脂酶A1的固定化条件并将固定化酶用于脱胶过程。以磁性Fe3O4/SiOx-g-P(GMA)复合粒子为载体,考察不同的固定化条件对固定化酶相对酶活的影响,然后将制得的磁性固定化PLA1用于大豆油脱胶中,并对其酶活再生进行有益研究。结果表明,最优固定化条件为:酶液添加量20mL,pH6.0,反应时间5h,此时酶活力最高;最佳脱胶条件为:反应时间6h、反应温度55℃、加酶量0.12g/kg、油相起始pH6.0。在最优条件下进行脱胶试验,测定脱胶油中的磷含量为12.5mg/kg,脱胶效果较好。将再生的磁性固定化磷脂酶A1再用于大豆油脱胶中,延长了磁性固定化磷脂酶A1的利用时间,降低了大豆油酶法脱胶的生产成本。     

脱胶对浓香菜籽油苯并芘去除的影响

以苯并芘超标的浓香菜籽毛油为原料,通过单因素实验和正交实验研究低温脱胶过程中,脱胶静置时间、脱胶温度、加水量和磷酸添加量对浓香菜籽油中苯并芘去除效果的影响。结果表明,在脱胶静置时间60 min、脱胶温度20℃、加水量3%、磷酸添加量0.1%的工艺条件下,浓香菜籽油中苯并芘去除率为83%,苯并芘含量为2.04μg/kg,水分含量为0.15%,所得浓香菜籽油风味浓郁醇厚,280℃加热试验合格。     

酶处理对菜籽油脱胶及品质的影响

采用磷脂酶A1（Lecitase ultra）对菜籽油进行脱胶实验，研究该酶对菜籽油脱胶及品质的影响。结果表明，Lecitase ultra在菜籽油脱胶中发挥了重要作用，能使菜籽油磷含量显著降低。通过正交试验得出Lecitase ultra应用于菜籽油脱胶的最佳工艺参数：pH值4．82、酶解温度37℃、加酶量150LU／kg油，油水混合物总含水量为2．69％，酶反应时间为3h，在此条件下脱胶油的磷含量为6．97mg／kg。同时，脱胶后菜籽油的酸价与过氧化值上升，色泽变浅，棕榈酸、油酸的含量下降，亚油酸、亚麻酸、花生一烯酸、芥酸的含量有所上升，其它几种脂肪酸的含量变化不大。     

复合重组磷脂酶用于大豆油脱胶的工艺优化

利用实验室前期构建的重组大肠杆菌所产磷脂酶A1（ p h o s p h o l i p a s e A 1, P L A 1）和磷脂酶C（phospholipase C,PLC）进行大豆油酶法脱胶研究,探讨自主开发重组酶进行酶法脱胶的可行性。以诺维信商品酶Lecitase Ultra™为对照,研究酶法脱胶反应温度、反应pH值、反应时间、搅拌速率、复合磷脂酶添加量工艺参数对大豆油脱胶的影响,并采用正交试验对脱胶工艺条件进行优化。研究结果表明,大豆油复合酶法脱胶的最佳工艺参数为：反应温度45 ℃、反应pH 6.5、反应时间3 h、搅拌速率300 r/min、PLA1和PLC添加量分别为7 940 U/kg和23 130 U/kg。复合磷脂酶对大豆油脱胶的效果与诺维信商品酶Lecitase Ultra™基本一致,大豆油磷含量可降至5 mg/kg以下,能够满足物理精炼的要求,为进一步开发具有知识产权的食品级油脂脱胶用酶制剂产品提供了理论依据。     

菜籽毛油酸法脱胶工艺条件的优化

研究酸种类、酸添加量、水添加量、酸处理温度、酸处理时间对菜籽毛油脱胶效果的影响.在单因素试验基础上,利用响应面分析法对菜籽毛油酸法脱胶工艺进行优化.优化的工艺条件为:酸处理温度60℃,50％柠檬酸添加量0.22％(占油质量),水添加量3.34％(占油质量),酸处理时间24.78 min.在优化条件下,脱胶菜籽油磷含量为15.67 mg/kg,脱胶率达93.76％,与模型预测值14.70 mg/kg,脱胶率94.15％很接近.     

大孔树脂固定化磷脂酶A1及其用于菜籽油脱胶工艺的优化

选择8种大孔树脂对磷脂酶A1进行固定化,结果表明,离子交换树脂D001的固定化效果最好,其优化的最佳条件为缓冲液pH5.0、酶添加量1.5mL/g、固定化时间4h,在该条件下获得的固定化酶活力为665.8U/g。将固定化酶用于菜籽油脱胶实验,经响应面优化确定最优脱胶条件为固定化酶添加量1.8g/kg、反应时间3.6h、反应温度51℃、反应pH5.5,在此条件下得到的脱胶油中磷含量为5.82mg/kg。将固定化酶重复脱胶5次后,仍保留初始酶活力的47.9%,脱胶油中磷含量为9.78mg/kg。     

酶法在新菜籽油水化脱胶中的应用

一般来说,新菜籽油的水化脱胶较陈菜籽油难,新菜籽油采用常规的水化脱胶往往在280℃加热试验不合格或用户使用时入锅后易起沫,储存稳定性差,影响产品的销售。其主要原因是油中残磷量高。经证实,新菜籽油中含有较多的非水化磷脂,用水化方法较难脱除。为此,我们将新型磷脂酶A1应用于新菜籽油脱胶中,取得了非常满意的效果。新菜籽油脱胶后油中含磷量为5~7 mg/kg,杜绝了脱胶菜籽油入锅后起沫现象,成品油具有令人满意的风味,储存稳定性好。1材料与方法1·1原料、试剂1·1·1原料菜籽毛油:许昌山花实业有限公司。1·1·2试剂新型磷脂酶A1:用水稀…     

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

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.     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

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.     

European priorities for research to support legislation in the area of food contact materials and articles

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.     

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