酶法提取鲟鱼油工艺的研究

本实验以鲟鱼加工下脚料为原料,研究酶法提取鲟鱼鱼油的工艺条件,比较不同提取方法对鱼油提取质量的影响,对3 种抗氧化剂在鱼油提取过程中的抗氧化性能进行了研究。结果表明,鱼油提取的最佳工艺条件为：酶量0.6%,水解时间2h,水解温度40℃,pH7,该工艺条件对鲟鱼内脏鱼油的提取效果明显好于氨法、钾法和蒸煮法,提取鱼油的过氧化值略高于氨法和钾法,但低于蒸煮法。TBHQ、VC、茶多酚三种抗氧化剂对鱼油抗氧化作用以TBHQ 效果最好。应用本法从鲟鱼肚及鲟鱼内脏提取的鱼油含有大量的不饱和脂肪酸,脂肪酸的不饱和程度与咸海卡拉白鱼接近,明显高于淡水养殖鱼类,是加工鱼油的良好来源。     

天然抗氧化剂对鳡鱼内脏油的抗氧化研究

以过氧化值为指标,以空白样和添加TBHQ样为对照,采用Schaal烘箱法研究了茶多酚、迷迭香酸、二氢杨梅素与VE4种天然抗氧化剂对鳡鱼内脏油的抗氧化效果。结果表明,当添加量均为0.02%时,其对鳡鱼内脏油抗氧化效果强弱为:TBHQ二氢杨梅素茶多酚迷迭香酸VE;茶多酚、迷迭香酸和二氢杨梅素最适添加量分别为0.04%、0.06%和0.04%;VC对茶多酚和二氢杨梅素均具有一定的增效作用;复配天然抗氧化剂的最佳组合为0.02%二氢杨梅素+0.02%茶多酚,并以0.02%的VC为增效剂;复配天然抗氧化剂对鳡鱼内脏油的抗氧化效果明显好于单一天然抗氧化剂的,且接近于TBHQ的。     

几种抗氧化剂对棉籽油氧化稳定性的影响

利用Rancimat法研究3种天然抗氧化剂迷迭香提取物、茶多酚、维生素E(VE)及合成抗氧化剂特丁基对苯二酚(TBHQ)对棉籽油抗氧化性能的影响.通过在棉籽油样品中添加不同质量浓度的单一和复合配比的抗氧化剂,分别测定诱导时间并考察抗氧化效果.结果表明,在棉籽油中单一抗氧化剂的抗氧化性能依次为TBHQ＞迷迭香＞茶多酚＞VE;在复合抗氧化剂组合中,迷迭香提取物与茶多酚以3∶1进行复配时具良好的协同增效作用;当3种天然抗氧化剂与TBHQ进行复配时,其抗氧化效果优于同等质量浓度的单一天然抗氧化剂.     

水合法提取罗非鱼鱼油及其脂肪酸组成分析

以冻干的罗非鱼粉为原料,采用酶解法和稀碱水解法分别提取罗非鱼鱼油,通过单因素试验和正交试验,确定两种水合法的最佳工艺条件,并采用气相色谱法分析罗非鱼鱼油脂肪酸组成。结果表明:稀碱水解法提取罗非鱼鱼油最佳工艺条件为料液比1∶3、pH 7.5、水解时间30 min、盐析量2.5%、盐析时间25 min、水解温度65℃;酶解法提取罗非鱼鱼油最佳工艺条件为料液比1∶3、加酶量0.6%、pH 9、酶解温度55℃、酶解时间2 h;在最佳工艺条件下,稀碱水解法的提油率为(32.13±0.07)%,略高于酶解法的(28.91±0.18)%;稀碱水解法提取罗非鱼鱼油n-3不饱和脂肪酸含量为(5.192±0.280)%,高于酶解法的(4.991±0.099)%。     

虾青素联合茶多酚对南湾鳙鱼油抗氧化作用的研究

目的:分析虾青素联合茶多酚对南湾鳙鱼进行保鲜的可行性。方法:三氯甲烷-乙醇法从南湾鳙鱼肉糜中提取鱼油,将虾青素和油溶性茶多酚的混合物添加到在烘箱强化保存条件下(60℃65℃)的鱼油中,定时测定鱼油酸价、过氧化值等指标的变化,并和虾青素、茶多酚、叔丁基对苯二酚(TBHQ)、丁基羟基茴香醚(BHA)、维生素E五种单一抗氧化剂对鱼油的抗氧化作用进行比较,考查虾青素和茶多酚联合作用对南湾鳙鱼油抗氧化性能的影响。结果:鱼油中添加抗氧化剂可明显抑制酸价和过氧化值的上升,单一抗氧化剂对南湾鳙鱼油的抗氧化性能表现为:TBHQ>虾青素>油溶性茶多酚>BHA>维生素E,虾青素联合茶多酚对南湾鳙鱼油的抗氧化作用和TBHQ相当,0.02%虾青素+0.02%茶多酚的复合抗氧化剂可使南湾鳙鱼油在20℃条件下的预期贮藏期从20d延长到120d。结论:虾青素联合茶多酚对南湾鳙鱼油具有良好的抗氧化作用,鱼油中二者的添加量为0.02%虾青素+0.02%茶多酚。     

天然抗氧化剂对鱼油抗氧化作用的影响

鱼油中含有具有双键的不饱和脂肪酸性物质,在贮存过程中易被氧化生成过氧化物。研究以禹王制药自制鱼油为研究对象,研究了天然VE、茶多酚、蜂胶和迷迭香抗氧化物对鱼油抗氧化作用的影响。试验结果表明,天然VE、茶多酚和迷迭香提取物对鱼油的抗氧化效果较好,将三者进行复配得到最适添加量为天然VE 0.04%、茶多酚0.06%、迷迭香提取物0.08%,在此条件基础上,40℃,加热20 min时,鱼油的过氧化值为4.47 meq/kg。     

草鱼内脏油的精制及阻抑鱼油氧化条件的研究

目的:研究草鱼内脏油精制条件,并比较不同抗氧化剂对鱼油的抗氧化作用.方法:用真空提油法提取粗草鱼内脏油,通过脱胶、脱酸、脱色、脱臭工艺精制鱼油,以过氧化值(POV)和硫代巴比妥酸值(TBARS) 为指标,在60℃条件下,对VC、VE、BHT、PG四种抗氧化剂进行筛选并比较.结果与结论:最佳的精制条件为:利用50%的磷酸脱胶,添加量为油量的1%;用浓度为3.65%的氢氧化钠脱酸,添加量为油量的1.5%;用活性炭和活性白土脱色,二者比例为1:20,添加量为油量的2.1%;在真空度为0.085kPa的条件下脱臭,时间为60min.不同抗氧化剂对鱼油的抗氧化能力为:0.01% PG ＞0.02% BHT＞0.1% VE＞0.2% VE＞0.2% VC.     

几种抗氧化剂对鱼油的抗氧化效果的研究

用3种新型的食品抗氧化剂——植酸钠、茶多酚、特丁基对苯二酚（TBHQ）添加到纯鱼油中，在5℃和20℃的条件下贮存，对其过氧化值（POV）和酸价（AV）进行测试和分析，并比较它们在鱼油中的抗氧化效果。     

复配天然抗氧化剂对食用油脂抗氧化效果研究

对天然抗氧化剂复配配方对食用油的抗氧化能力进行研究。根据正交试验结果,各种天然抗氧化剂在组分中的主次因素为迷迭香提取物＞甘草提取物＞茶多酚＞ VE,优化得出复合天然抗氧化剂的复配组合为迷迭香0.08%、茶多酚0.06%、甘草提取物0.08%、VE0.01%。此优化的配方对食用油的抗氧化能力弱于TBHQ,但强于BHA 和BHT。     

天然抗氧化剂对斑点叉尾鮰内脏精炼鱼油的抗氧化效果研究

以过氧化值(POV)为指标,采用Schaal烘箱法研究了D-异抗坏血酸钠、迷迭香、茶多酚对斑点叉尾鮰内脏精炼鱼油的抗氧化效果,结果表明当抗氧化剂的添加浓度为0.02%时,抗氧化性能由大到小顺序为茶多酚>迷迭香>D-异抗坏血酸钠,茶多酚的抗氧化效果与其浓度呈剂量效应关系。添加维生素C和柠檬酸对茶多酚的抗氧化效果均有协同增效作用,但维生素C对茶多酚抗氧化能力的增效略大于柠檬酸。     

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.     

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.     

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.     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

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.     

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.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.