滇牡丹籽油与凤丹牡丹籽油品质及活性对比研究

以超临界CO2萃取法提取的滇牡丹籽油与凤丹牡丹籽油为原料,以酸值、碘值、皂化值、过氧化值及两种牡丹籽油脂肪酸组成为品质评价指标,以DPPH自由基清除率及对酪氨酸酶抑制率为活性评价指标,对比研究二者品质和活性。结果表明:滇牡丹籽油与凤丹牡丹籽油的酸值(KOH)分别为1.628 mg/g和1.724 mg/g,碘值(I)分别为172 g/100 g和168 g/100 g,滇牡丹籽油的皂化值(KOH)为186.4 mg/g,在药典规定的注射用油皂化值(KOH)(185~200 mg/g)范围内。二者清除DPPH自由基能力均高于橄榄油,滇牡丹籽油清除DPPH自由基能力稍低于凤丹牡丹籽油,而抗酪氨酸酶活性强于凤丹牡丹籽油。     

牡丹籽油的理化指标和脂肪酸成分分析

用索氏提取法获得牡丹籽油,经皂化、甲酯化后用毛细管GC-MS法对其脂肪酸成分进行分析,面积归一化法计算相对含量,同时按国家标准对牡丹籽油的理化指标进行了检测.结果表明,牡丹籽油中共有17种脂肪酸成分,主要为亚麻酸、油酸、亚油酸等,不饱和脂肪酸占83.05%,饱和脂肪酸占14.33%;牡丹籽油的酸值(KOH)为1.784 mg/g,碘值(I)为176.2 g/100 g,皂化值(KOH)为194.4 mg/g,相对密度0.930 7.说明牡丹籽是一种良好的油料资源,适宜开发利用.     

不同贮藏条件下水酶法牡丹籽油的 氧化稳定性与货架期预测

旨在为水酶法牡丹籽油的品质控制提供理论依据,探究不同贮藏条件下水酶法牡丹籽油的氧化稳定性,并对其货架期进行预测。采用Schaal烘箱模拟加速氧化法,探究了抗氧化剂、包装材料、温度对牡丹籽油过氧化值的影响,并进行了氧化动力学分析,采用Arrhenius方程进行拟合,建立了水酶法牡丹籽油货架期预测模型。结果表明：不同抗氧化剂的抗氧化效果排序为0.01%柠檬酸+0.01%TBHQ＞0.02%TBHQ＞0.02%柠檬酸>0.2%γ-谷维素;包装材料的抗氧化效果排序为棕色PET瓶＞棕色玻璃瓶＞透明PET瓶＞透明玻璃瓶;随着温度升高,牡丹籽油的过氧化值明显增加;建立的货架期预测模型预测牡丹籽油在10、20、30 ℃下的货架期分别为117、77、51 d,其实测货架期分别为134、90、60 d。综上,使用抗氧化剂、避光、低温均能有效延缓水酶法牡丹籽油的氧化进程,建立的水酶法牡丹籽油货架期预测模型准确率良好。     

天然抗氧化剂对牡丹籽油氧化稳定性的影响

采用Schaal烘箱法,以合成抗氧化剂二叔丁基羟基甲苯(BHT)为阳性对照,研究茶多酚、迷迭香提取物、生育酚、大豆异黄酮、葡萄籽提取物天然抗氧化剂对牡丹籽油氧化稳定性的影响。结果表明,5种天然抗氧化剂均能提高牡丹籽油的氧化稳定性,但单独使用的效果要差于BHT;0.2 g/kg(以底油质量计,下同)迷迭香提取物+0.2 g/kg生育酚的协同抗氧化效果较接近于BHT;柠檬酸对茶多酚、迷迭香提取物、生育酚均有抗氧化增效作用,其中0.2 g/kg柠檬酸+0.4g/kg迷迭香提取物的抗氧化效果要好于0.2 g/kg的BHT。     

2种酚类抗氧化剂对牡丹籽油氧化稳定性影响研究

通过Schaal烘箱实验,以过氧化值(PV)、茴香胺值(ρ-AnV)、全氧化值及脂肪酸组成为指标研究2种天然酚类抗氧化剂咖啡酸和阿魏酸及合成抗氧化剂TBHQ对牡丹籽油氧化稳定性影响,并建立牡丹籽油氧化动力学模型,以Rancimat法预测其货架期。研究表明:0.02%咖啡酸和0.02%阿魏酸对牡丹籽油都有一定的抗氧化效果,与不添加抗氧化剂相比货架期延长2.65、2.55倍,但较TBHQ仍有提升空间,几种抗氧化剂能力大小为TBHQ咖啡酸阿魏酸。咖啡酸、阿魏酸能够有效延缓牡丹籽油中α-亚麻酸等不饱和脂肪酸分解,提高牡丹籽油氧化稳定性和产品质量,能够作为高效、安全的天然抗氧化剂应用于油脂工业。     

永靖紫斑牡丹籽油与凤丹牡丹籽油理化性质与脂肪酸组成分析

采用超声波辅助提取法对甘肃永靖产紫斑牡丹籽和凤丹牡丹籽中油脂进行提取,对其主要理化指标进行测定,采用气相色谱-质谱联用仪对其脂肪酸组成进行分析。结果表明:紫斑牡丹籽与凤丹牡丹籽得油率分别为(27.08±3.09)%和(28.69±2.69)%,紫斑牡丹籽油与凤丹牡丹籽油酸值(KOH)、碘值(I)、皂化值(KOH)、过氧化值分别为(2.13±0.08)、(2.05±0.11)mg/g;(178.13±3.18)、(172.56±3.58)g/100 g;(188.23±3.49)、(183.56±3.29)mg/g和(1.47±0.06)、(1.55±0.04)mmol/kg,符合粮食行业标准LS/T 3242—2014《牡丹籽油》。紫斑牡丹籽油与凤丹牡丹籽油的主要脂肪酸组成相似,以亚麻酸、亚油酸、油酸、硬脂酸和棕榈酸为主,不饱和脂肪酸含量均接近90%,其中ω-3系列亚麻酸的含量尤其突出,分别达到44.90%和47.48%,远高于世界卫生组织推荐的多不饱和脂肪酸含量高于8.00%的保健型营养油脂标准。综合分析,永靖紫斑牡丹籽油和凤丹牡丹籽油是优质的ω-3脂肪酸保健食用油。     

茶多酚对牡丹籽油氧化稳定性的影响及货架期预测

以牡丹籽油为原料,以过氧化值为稳定性评价指标,采用Schaal烘箱加速氧化法探讨茶多酚添加量、抗氧化剂种类及贮存温度对牡丹籽油氧化稳定性的影响,根据Arrhenius经验公式推导出货架期模型,并对牡丹籽油货架期进行预测。结果表明,茶多酚在GB 2760—2014规定的添加量范围内对牡丹籽油的抗氧化作用随添加量增加而增大;添加0. 02%(以牡丹籽油质量计)的抗氧化剂对牡丹籽油的抗氧化效果依次为TBHQ BHT茶多酚,但对酸价的影响均不大;根据货架期模型可预测添加0. 02%茶多酚的牡丹籽油室温(25℃)下货架期为645. 30 h。     

正交试验优化牡丹籽油的溶剂萃取脱酸工艺

研究牡丹籽毛油的溶剂萃取脱酸工艺,通过单因素试验和正交试验得到牡丹籽毛油的最佳萃取脱酸工艺条件为：以95%乙醇溶液为萃取溶剂,萃取次数3 次、料液比1∶2.5（g/mL）、萃取温度40 ℃、萃取时间20 min。在该最佳条件下,游离脂肪酸脱除率为93.12%,脱酸得油率为83.23%;牡丹籽油的酸值由10.18 mg KOH/g降到0.70 mg KOH/g,仍然保持牡丹籽油特有的清香味,达到后续深加工和开发利用的品质要求。     

水酶法提取牡丹籽油的研究

采用水酶法从牡丹籽中提取牡丹籽油,通过对比实验,选择了三步酶解结合二次破乳的工艺流程。5 g牡丹籽粉三步酶解结合二次破乳提取牡丹籽油的优化条件为:料水比1∶5,细胞壁多糖水解酶(纤维素酶与果胶酶配比2∶1)加酶量1.5 mL,酶解时间2.5 h;α-中温淀粉酶加酶量0.6 mL,酶解时间45 min;碱性蛋白酶加酶量0.18 g,酶解时间2 h;冷冻解冻破乳法,-20℃冷冻18 h后50℃解冻2 h。在优化条件下取200 g牡丹籽粉提取牡丹籽油,其游离油得率达到17.6%,总油得率达到25.4%,所得牡丹籽油品质良好,未检出过氧化物,酸值(KOH)3.5 mg/g,碘值(I)177.09 g/100 g,皂化值(KOH)173.07 mg/g;牡丹籽油中不饱和脂肪酸含量达到92.77%,其中亚麻酸含量37.33%,亚油酸含量31.13%,油酸含量24.31%。水酶法提取牡丹籽油具有牡丹籽粉无需干燥,整个提油过程温度不超过70℃的优点,可大大减少提取过程中油脂的氧化。     

特种植物油中甾醇总量及组成分析

通过气相色谱法对牡丹籽油、核桃油、南瓜籽油、葡萄籽油四种特种植物油中的甾醇总量及组成进行分析研究。结果表明,牡丹籽油甾醇总量为240.0 mg/100 g,其主要组分是β-谷甾醇、Δ5,23-豆甾二烯醇和Δ5-燕麦甾烯醇;核桃油甾醇总量为100.5 mg/100 g,其主要组分是β-谷甾醇;南瓜籽油甾醇总量为299.6~358.4 mg/100 g,其主要组分是β-谷甾醇、Δ5,24-豆甾二烯醇和Δ7-燕麦甾烯醇;葡萄籽油甾醇总量为222.5~234.9 mg/100 g,其主要组分是β-谷甾醇、菜油(芸薹)甾醇和豆甾醇。分析结果为特种植物油的开发及加工提供了基础数据及技术支撑。     

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.     

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.     

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.     

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.     

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.