四级浓香菜籽油酶法脱胶工艺条件优化

选取磷脂酶PLA_1,对四级浓香菜籽油进行酶法脱胶工艺研究。分别研究了酶添加量、50%柠檬酸添加量、去离子水添加量、酶解时间对四级浓香菜籽油酶法脱胶效果的影响。在单因素实验的基础上,采用响应面实验设计,对酶法脱胶工艺条件进行优化。结果表明:四级浓香菜籽油酶法脱胶最佳工艺条件为水浴温度55℃、酸反应时间3 min、酶添加量22 mg/kg、50%柠檬酸添加量260mg/kg、去离子水添加量2%、酶解时间120 min,在该条件下酶法脱胶油磷脂含量为22. 26 mg/kg,酸价(KOH)为2. 31 mg/g,收率为96. 81%。     

冷榨芝麻油酸法脱胶工艺

以冷榨芝麻油为原料,研究酸法脱胶工艺参数对其脱胶效果的影响。在单因素实验基础上,通过正交实验得出柠檬酸脱胶的最佳条件:脱胶温度60℃,柠檬酸添加量5.0g/kg,加水量2.5%,脱胶时间45min,该条件下脱胶率为72.9%,脱胶油中磷脂含量为54.05mg/kg。脱胶芝麻油除过氧化值升高外,其颜色变浅、酸值和不皂化物含量降低。     

菜籽油磷脂酶C脱胶工艺优化及效果分析

分别研究了柠檬酸添加量、酶加入量、温度、加水量和时间5个单因素对磷脂酶C(PLC)脱胶效果的影响,在单因素基础上,采用响应面试验设计,对主要脱胶工艺参数进行优化,得到最佳条件:柠檬酸添加量5.80m L/kg,加酶量12.60 m L/kg,酶解温度42.20℃,在该条件下验证,菜籽毛油磷含量由693 mg/kg降低至7.85mg/kg。采用棒状薄层色谱-氢火焰离子化检测器(TLC-FID)对毛油与脱胶油中甘油酯含量进行检测,结果表明:脱胶油中甘一酯的含量变化不明显,甘二酯含量从约2.5%增加到约6.5%,而甘三酯的含量从约93%下降到约89%;而同样采用TLC-FID对水化脱胶磷脂与PLC脱胶磷脂中的溶血磷脂进行检测,分析得知,PLC脱胶磷脂中溶血磷脂含量比水化脱胶磷脂中的高出约50%,酶法脱胶的酶解率显著升高。研究结果表明,磷脂酶C脱胶比常规水化脱胶更有效和彻底,可为油脂精炼提供了一定理论参考。     

响应面法优化小桐子油酸法脱胶预处理工艺

用于制备航空煤油的植物油含大量的胶质(以磷脂为主),需对其进行脱胶预处理。采用酸法脱胶研究了柠檬酸添加量、脱胶温度、加水量、搅拌转速、活性炭添加量、乙醇胺(MEA)添加量和MEA反应时间对小桐子油脱胶效果的影响。在单因素实验基础上,根据Box-Behnken中心组合实验设计原理,用响应面法优化工艺条件。结果表明:最佳工艺条件为质量分数45%的柠檬酸添加量2. 12%、MEA添加量0. 52%、MEA反应时间26. 23 min、搅拌转速258. 47 r/min、脱胶温度50℃、加水量2%、活性炭添加量2%,在此条件下,模型预测脱胶小桐子油磷含量为0. 61 mg/kg,实测值为0. 65 mg/kg,误差率为6. 55%,证明模型可靠。     

磷脂酶A1对大豆毛油脱胶效果的影响

以大豆毛油为原料,研究磷脂酶A1 添加量、柠檬酸溶液添加量、脱胶温度和脱胶时间对脱胶效果以及中性油脂肪酸和甘油酯组成的影响。结果表明,磷脂酶A1 脱胶的最佳反应条件为20 mg/100 g 油的磷脂酶A1、0.15 mL 45% 柠檬酸溶液、50 ℃脱胶温度、4 h 反应时间。在最佳的脱胶工艺条件下,磷脂酶A1 脱胶中性油中含磷量降至0.47 mg/kg,油脂得率（95.55%）高于酸化脱胶中性油的得率（92.94%）。酶法脱胶中性油与毛油的脂肪酸和甘油酯组成相比,酶法脱胶中性油的脂肪酸组成没有明显变化,甘油酯组成中的甘一酯和甘二酯相对含量减少、甘三酯相对含量增加;与酸化脱胶油脚相比,磷脂酶A1 脱胶油脚中溶血磷脂（溶血磷脂酰胆碱、溶血磷脂酰乙醇胺和溶血磷脂酰肌醇）的相对含量增加至48%。     

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。     

大豆油酶法脱胶的生产应用

以大豆毛油为原料,添加磷脂酶进行酶法脱胶,通过生产实际应用,确定酶法脱胶工艺参数为:磷脂酶A1和磷脂酶C混合酶用量45 mg/kg,pH 5,加水量2％,反应温度52℃,反应时间2h.在此条件下,脱胶油磷含量可降至5 mg/kg,精炼成品油总磷含量可降至1.4 mg/kg,非水化磷脂去除率达到99.3％以上,精炼成品油得率可达97.3％.对比特殊脱胶方法,精炼成品油经济效益提高了74.42元/t.     

磷脂酶C对大豆原油脱胶效果的研究

为了避免传统脱胶方式引起的化学品消耗大、水耗高,而且脱胶油得率低、残磷量高等问题,以大豆原油为原料,采用磷脂酶C对其进行酶法脱胶,考察加酶量、柠檬酸添加量、脱胶温度和脱胶时间对磷脂脱除和脱胶油得率的影响。结果表明,磷脂酶C脱胶的最佳反应条件为0.45 g/mL 柠檬酸添加量0.15 mL（100 g原油）、加酶量40 mg/100 g（以油质量计）、脱胶温度50℃、脱胶时间4 h。在最佳条件下,磷脂酶C脱胶油中含磷量降至1.00 mg/kg。酶法脱胶油的脂肪酸组成和各脂肪酸相对含量与大豆原油相比无显著差异。与酸化脱胶相比,酶法脱胶油的得率无显著差异,油中甘一酯和甘二酯相对含量分别增加了0.49、1.15百分点,甘三酯相对含量减少了2.28百分点,油脚中磷脂的组成及各组分相对含量无变化。     

葵花籽油酶法脱胶工艺优化

选取米曲霉磷脂酶C（PLC）对葵花籽油进行酶法脱胶。采用单因素试验分别研究了混合体系pH、酶解温度、酶解时间、加酶量和柠檬酸质量分数对葵花籽油酶法脱胶效果的影响。结果表明,葵花籽油酶法脱胶的最佳工艺条件为：混合体系pH 7.5,酶解温度25 ℃,酶解时间3 h,加酶量5 000 U/kg,柠檬酸质量分数20%（添加量0.1%）。在最佳工艺条件下,葵花籽油磷含量从55.8 mg/kg降至8.2 mg/kg,脱胶率为85.3%,达到植物油工业精炼要求（磷含量≤10 mg/kg）。     

微藻DHA油脂的酶法脱胶工艺研究

采用嗜热真菌(Thermomyces lanuginosus)产磷脂酶A1对裂殖壶菌产DHA毛油进行脱胶处理,以脱胶油磷含量、酸价为考查指标,先对脱胶时间、反应温度、加酶量和加水量等因素进行单因素实验,然后通过正交实验得出微藻DHA油脂的最佳脱胶条件为:脱胶时间3h,反应温度45℃,加酶量0.6mL/100g油,加水量为2mL/100g油;此条件下油脂中磷脂含量从158.1mg/kg降到4.6mg/kg,酸价变化较小。与传统的脱胶工艺相比,新型酶法脱胶优势明显,具有良好的应用前景。     

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.