不同精炼程度油茶籽油储藏品质变化研究

为了阐明不同精炼程度油茶籽油在储藏条件下的品质变化规律并为油茶籽油储藏技术提供参考依据,采用同一批油茶籽压榨制取4种不同精炼程度油茶籽油,研究了储藏期间油样的质量安全指标与生理活性物质的变化规律。结果表明:在整个储藏期间,毛油酸值上升最快,上升了29.85%;碱炼油的酸值和过氧化值上升最慢,分别上升了3.48%和5.97%,适度精炼油中油酸和亚油酸等不饱和脂肪酸的保存最好,且更有利于VE以及角鲨烯的保持。精炼油生理活性物质中VE和角鲨烯在储藏期间损失较多。从生理活性物质来看,适度精炼更有优势。在采用较好油茶籽油原料的基础上,通过适度精炼来保证油茶籽油储藏过程中的品质是可行的。     

贮藏条件对不同工艺生产的油茶籽油品质的影响

对不同工艺生产的油茶籽油,在不同贮藏条件下长期贮藏后的酸值、过氧化值和VE含量进行测定。结果
表明：各种成品油的酸值和过氧化值随贮藏时间的延长而上升,而VE的含量下降。全程低温工艺精炼的油茶籽油
经过长期贮藏后,其酸值和过氧化值的增加量与一级压榨油相当,但明显低于高温精炼油。在高温、光照等不良贮
藏条件下,低温工艺精炼的油茶籽油的优势很明显,品质劣变程度小。     

油茶籽油加工过程中理化性质和营养品质的变化

本研究通过测定精炼过程不同阶段油茶籽油的理化指标和营养成分的变化,研究精炼工艺对油茶籽油品质的影响。结果表明,毛茶油的酸值最高,为0.746 mg/g,碱炼油的酸值最低,仅为0.037 mg/g,碱炼过程酸值降低最多达95.04%。水洗脱水油的过氧化值最高,达5.81 meq/kg,脱臭油的过氧化值最低,仅2.22 meq/kg,整个过程过氧化值降低率为61.79%。从毛茶油到精炼油的加工过程中,茶多酚、α-生育酚和角鲨烯含量变化均呈递减趋势。毛茶油茶多酚、α-生育酚和角鲨烯的含量分别为54.698 5 μg/g、251.337 0、136.680 0 mg/kg,而脱臭油含量分别为25.134 1 μg/g、101.301 0、89.140 0 mg/kg。在精炼过程中脂肪酸种类和比例都有一定的变化,单不饱和脂肪酸比例降低0.188%,而饱和脂肪酸和反式脂肪酸比例分别增加0.029%和0.089%。精炼可降低酸值和过氧化值使油茶籽油达到食用油国家标准,但同时也造成茶多酚、α-生育酚和角鲨烯等活性成分的损失。因此应该提倡适度精炼以达到安全与营养的平衡。     

精炼过程对油茶籽油品质影响的研究

研究了精炼过程对油茶籽油品质的影响。结果表明:脱胶脱酸工序中油茶籽油酸值降低;脱色工序中油茶籽油色泽变浅、酸值上升、过氧化值降低;脱臭工序中油茶籽油中甾醇、α-生育酚、角鲨烯含量显著降低,分别降低了32.1%、16.6%、40.0%;冬化工序中因饱和脂肪酸结晶析出而使得油茶籽油碘值、不饱和脂肪酸含量和三油酸甘油酯含量升高;精炼过程中,油茶籽油脂肪酸组成和甘油三酯组成变化不大。     

全程低温精制工艺对油茶籽油主要活性成分的影响

油茶籽油含有多种具有生物活性的功能性营养成分,被誉为“东方橄榄油”.然而,初榨油茶籽油中还含有一些不良物质和浓重的气味,需要通过精炼去除后才能成为高质量的商业产品.由于大部分的生物活性物质是热敏感型化合物,因此精炼温度是影响精炼油茶籽油质量的关键工艺参数.通过适度降低传统的精炼温度,优化组合了一套油茶籽油全程低温精炼工艺.应用结果表明,优化的低温精制工艺不仅能有效地去除油茶籽油中的不良成分、产品质量完全符合国家质量标准(GB 11765-2003),而且能最大程度地保留油茶籽油中的活性营养成分.与传统的高温精炼工艺相比,低温精炼油中的甾醇、角鲨烯、维生素E和维生素D3的保留率分别提高了59.2％、54.3％、56.2％和67.8％.     

4种油茶籽油中多酚类物质的抗氧化活性比较研究

采用80%乙醇溶液分别提取雅安当地的白花和红花油茶籽毛油与精炼油中的多酚类物质,比较研究这4种油茶籽油中多酚类物质的抗氧化活性。结果表明:多酚类物质的含量分别为1.41(白花油茶籽毛油)、1.04(白花油茶籽精炼油)、0.75(红花油茶籽毛油)、0.68μg/mL(红花油茶籽精炼油);4种油茶籽油多酚类物质均表现出较强的抗氧化活性,并随多酚含量的增加而增强;白花油茶籽油中多酚类物质的抗氧化能力均强于红花油茶籽油中的;毛油相对于精炼油均具有更强的抗氧化作用;白花油茶籽毛油中多酚类物质的抗氧化活性不稳定。     

油茶鲜果预处理方式对低温压榨油茶籽油品质的影响

为更多地保留活性成分,提高油茶籽油品质,研究了油茶鲜果6种不同预处理方式(剥壳-摊晒、直接摊晒、堆沤-摊晒、剥壳-烘干、直接烘干、堆沤-烘干)对油茶籽主要成分以及低温压榨油茶籽油中3种理化指标(酸值、过氧化值、多环芳烃)和4种微量活性成分(维生素E、维生素K₁、角鲨烯、多酚)的影响。结果表明：油茶鲜果预处理方式对油茶籽主要成分(脂肪、蛋白质、淀粉)影响不大;6种不同预处理方式对低温压榨油茶籽油的理化指标和微量活性成分均有一定的影响,其中剥壳-烘干处理油茶鲜果在油茶籽油的酸值、多环芳烃、维生素E、角鲨烯指标上较其他预处理方式存在一定优势。综上,采用剥壳-烘干对油茶鲜果进行预处理,可在一定程度上提高油茶籽油品质。     

不同条件对油茶籽油储藏稳定性的影响

研究了不同加工工艺(压榨毛油、压榨精炼油、浸出精炼油)、不同容器(铁罐、无色玻璃瓶和塑料瓶)及不同光照条件(光照、避光)下油茶籽油的储藏稳定性.结果显示:不同加工工艺油茶籽油样品中浸出精炼油和压榨精炼油储藏稳定性较好,压榨毛油最差;光照是影响油茶籽油储藏稳定性的关键因素,油茶籽油包装及储藏要尽量采用不透光材料或避光储藏;3种容器材料中,铁罐储藏效果最好,玻璃瓶次之,塑料瓶最差.     

油茶籽油适度精炼温度优化及其对特征组分的影响

为探究温度优化后的适度精炼工艺对油茶籽油特征组分的影响,对适度精炼的4个工序的温度进行了优化,并采用主成分法分析适度精炼对脂肪酸组成、生育酚、甾醇和角鲨烯含量的影响.结果 表明,油茶籽油的最佳适度精炼温度为脱胶55℃、脱酸55℃、脱色90℃和冬化0℃.精炼后,油茶籽油中的脂肪酸、甾醇、角鲨烯和生育酚含量均显著降低.主成...     

制油方式对油茶籽油品质及活性成分的影响

研究了普通螺旋榨、溶剂浸提、包饼液压和快速液压4种制油方式对油茶籽油品质及营养活性物质的影响。结果表明,在4种制油方式中,快速液压榨所得油的酸值与过氧化值最低,普通螺旋榨的最高。快速液压油脂肪酸组成中油酸含量最高,为82.85%;油中的α-生育酚含量最高,为29.8mg/100g,且角鲨烯与β-谷甾醇保存较好。单从油茶籽油品质及活性成分的保持上来看,快速液压是一种较为理想的制油方式。     

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