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。     

精炼过程中油茶籽油活性成分和抗氧化性的变化

研究了精炼工艺对油茶籽油活性成分和抗氧化性的影响。结果表明:经过精炼,油茶籽油中的活性成分不断降低,碱炼后,多酚损失率达到了80.50%;脱色和脱臭后,生育酚损失率分别达到了13.05%和20.69%,甾醇的损失率分别达到了12.85%和13.09%;脱色后,角鲨烯损失率达到了24.99%。抗氧化性方面,油茶籽油对3种自由基的清除能力有一定差异,强弱顺序为ORAC自由基ABTS自由基DPPH自由基。     

不同生产工艺对油茶籽油理化指标和脂质伴随物的影响

目的 研究油茶籽油加工过程中全生产工艺对油理化指标和脂质伴随物的影响。方法 首先收集不同预处理方式、不同制油工艺、不同精炼阶段生产的油茶籽油,其次对其酸价、过氧化值等质量指标、脂肪酸组成、生育酚、角鲨烯、甾醇等活性脂质伴随物进行检测,最后进行分析讨论。结果 蒸汽和热风预处理油茶籽对油茶籽油脂肪酸组成影响不大,可以使油中的多酚含量增加76.79%和59.81%,热风预处理会增加植物甾醇的含量。在制油环节,浸出工艺会大幅度增加油茶籽油的酸价、过氧化值,且有苯并[a]芘的产生,对油品影响严重。精炼结束后压榨油茶籽油的酸价下降了65.57%,苯并[a]芘未检出,生育酚、甾醇、角鲨烯和多酚含量分别损失100%、22.61%、89.69%和79.19%。精炼工艺仅保留脱胶沉淀,不经脱色、脱酸脱臭和冬化等工序,油茶籽油的脂肪酸组成保持不变,过氧化值下降30.30%,苯并[a]芘未检出,还可使生育酚、角鲨烯、多酚和甾醇等活性脂质伴随物的保留率达85%以上。结论 油茶籽预处理会促进脂质伴随物的溶出,精炼工艺能提高油茶籽油质量但会对脂质伴随物含量造成一定损失,浸出工艺相较压榨工艺对油品易造成较大影响。在实...     

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...     

油茶籽油中苯并(a)芘的形成与控制

通过研究热榨、冷榨、浸出和不同精炼工序对油茶籽油中苯并(a)芘(BaP)含量的影响,探索了茶籽油中BaP的形成原因。结果表明,冷榨毛油中BaP含量为(2.56±0.0804)μg/kg,其无需精炼即可达到食用安全要求(≤10μg/kg);导致传统热榨-浸出制油工艺中油脂的BaP超标的主要原因是高温而不是浸出溶剂;碱炼工序会促进BaP含量大量增加,高温脱臭工序也会提高BaP含量(增幅约84%～247%);而脱色、冬化工序可以降低油脂中的BaP(降幅约71.5%～85.9%)。因此,在油茶籽油生产与加工过程中,应尽量避免使用高温条件;毛油精炼工艺应包含脱色和冬化工序,同时应控制碱炼与脱臭工艺条件,使茶籽油得到适度精炼,以确保其食品质量安全。     

精炼对油茶籽油三萜类化合物含量的影响

不同精炼工序油茶籽油经中性氧化铝柱层析分离,正己烷洗脱后,采用GC-MS测定各工序油茶籽油11种三萜类化合物含量,研究精炼对油茶籽油中三萜类化合物含量的影响。结果表明：环阿屯醇和β-香树脂醇为油茶籽油中两种主要的三萜类化合物,毛油中含量分别达到1 043.30 mg/kg和878.24 mg/kg;除羽扇豆醇外,其他三萜类化合物含量随着脱酸、脱色、脱臭精炼过程不断降低,其中β-谷甾醇、β-香树脂醇含量受脱酸影响较大,角鲨烯含量受脱色过程影响较大,环阿屯醇含量受脱色和脱臭影响较大;各精炼工序油茶籽油中均未检出菜籽甾醇、熊果醇和桦木醇。通过研究初步探明油茶籽油主要三萜类化合物类型,为油茶籽油的适度精炼提供数据支撑。     

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。     

茶籽油精炼过程中理化指标的变化及精炼条件选择

对茶籽油在各精炼阶段中主要理化指标的变化及精炼条件进行了研究,结果表明,脱色工序使油中过氧化值下降,脱臭工序中油脂的酸值与色泽变化较大,碱炼与冬化两个工序对茶籽油的脂肪酸组成影响比较大,碱炼茶籽油中硬脂酸含量稍有降低,而冬化油中椋榈酸下降幅度较大.茶籽油精炼较佳工艺条件为:碱炼油温30℃,碱液浓度18°B'e,超量碱0.2%,脱色温度100～110℃,活性白土用量2.5%～3.0%,时间25min,脱臭温度180℃,时间1h;冬化温度6～8℃.结晶时间为8h.     

茶籽油精炼过程中主要理化指标的变化

本文对茶籽油在各精炼阶段中主要理化指标的变化情况进行了研究,结果表明,茶籽油经碱炼后酸值和色泽大幅下降,脱色后油中过氧化值下降,脱臭工序中油脂的酸值与色泽变化较大. 气相色谱分析表明,碱炼与冬化两个工序对茶籽油的脂肪酸组成影响比较大,碱炼茶籽油中硬脂酸含量降低,而冬化油中棕榈酸含量下降幅度较大.     

不同生产工艺对油茶籽油中苯并(a)芘含量的影响

研究了压榨、浸出和水酶法3种制油工艺和不同精炼工序对油茶籽油中苯并(a)芘含量的影响.结果表明:在3种制油工艺中,水酶法制取的油脂无需精炼即可使其苯并(a)芘含量达到安全要求;导致传统热榨制油工艺中油茶籽油苯并(a)芘超标的主要原因是高温;在油茶籽油精炼工艺中,碱炼工序会促进苯并(a)芘含量大量增加,脱臭工序也会造成苯并(a)芘一定程度地增加,而脱色、冬化工序可以降低油茶籽油中的苯并(a)芘,最终使其达到安全范围内.     

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