气相色谱法同时测定食品中的胆固醇和植物甾醇

建立气相色谱法同时测定食品中植物甾醇和胆固醇含量的分析方法,测定植物甾醇含量较高的常见植物油和同时含有胆固醇及植物甾醇的样品。采用5α-胆甾烷为内标参照物,样品经皂化后提取,浓缩后正庚烷定容上机进样分析。胆固醇和植物甾醇在0.001～2.5 mg/mL质量浓度范围内线性良好,线性相关系数R2均大于0.99。方法的检出限为0.3 mg/100 g,定量限为1.0 mg/100 g,该方法相较于液相色谱法能有效将胆固醇和植物甾醇进行分离,具有步骤简单、重复性好、准确度和灵敏度高等特点。     

黑果枸杞油中脂肪酸、植物甾醇的组成及维生素A、维生素E的分析

对黑果枸杞油中脂肪酸、植物甾醇组成及维生素A、维生素E的含量进行测定。结果表明:黑果枸杞油中不饱和脂肪酸含量为90.0%,其中油酸、亚油酸、亚麻酸含量分别为17.9%、67.6%和4.0%;植物甾醇由β-谷甾醇、菜油甾醇和豆甾醇组成,总含量为489.2 mg/100 g;维生素A和维生素E的含量分别为0.3 mg/100 g和46.3 mg/100 g。黑果枸杞油是一种具有开发价值的新型植物油。     

HPLC-UV法测定植物甾醇中3种甾醇单体的含量

本文建立了一种利用紫外高效液相法(HPLC-UV)测定植物甾醇中菜油甾醇、豆甾醇和β-谷甾醇的方法。采用 Waters Symmetry C₁₈柱(4.6 mm×250 mm,5 μm),以乙腈和水为流动相等度洗脱,柱温30 ℃,流速1.0 mL/min,紫外检测波长为208 nm。实验结果表明:菜油甾醇、豆甾醇和β-谷甾醇在38 min内均能实现基线分离,线性范围分别为2.52~50.30、5.08~101.60、5.10~102.00 μg/mL时,甾醇单体的线性关系良好,相关系数r分别为0.9971、0.9989、0.9991,检测限为2.5 μg/mL;日内精密度在0.06%~3.06%范围内,日间精密度介于1.56%~6.61%;加样回收率介于92.74%~106.25%之间。本方法能够准确测定4种植物甾醇中3种甾醇单体的含量,其中大豆甾醇和木甾醇中3种甾醇单体的含量组成差异较大,大豆甾醇中菜油甾醇和豆甾醇的含量分别为163.80~251.23 mg/g和134.89~235.04 mg/g,远高于木甾醇中的菜油甾醇和豆甾醇含量,而木甾醇中β-谷甾醇含量为(685.10±7.55) mg/g,则明显高于β-谷甾醇在大豆甾醇中的含量。相对现有的高效液相方法,本方法实现了对混合甾醇中菜油甾醇、豆甾醇和β-谷甾醇3种甾醇单体的精确定量分析。     

HPLC法同时测定山药中的植物甾醇

建立了一种高效液相色谱法(HPLC)同时测定山药中的3种植物甾醇(菜油甾醇、豆甾醇和β-谷甾醇)含量的方法。样品使用甲醇提取,经皂化、萃取后用HPLC进行分析。色谱条件:SunFire C8色谱柱(4.6 mm×250 mm,5μm),流动相乙腈-水(92.5:7.5),检测波长205 nm。结果表明:山药中3种植物甾醇在一定浓度范围内呈现良好的线性关系,相关系数均不小于0.9997,样品检出限为0.50～0.52μg/mL,样品平均加标回收率在93.5%～97.2%,相对标准偏差均小于3.6%。经测定,山药中的植物甾醇含量为菜油甾醇67.1～79.8μg/g,豆甾醇28.8～36.7μg/g,β-谷甾醇129.6～154.5μg/g。该方法操作简便、结果准确度高且重复性好,可作为山药中植物甾醇含量同时测定的方法。     

超高效液相色谱法检测固体粉状保健品中豆甾醇、菜油甾醇、β-谷甾醇的含量

目的 建立超高效液相色谱检测固体粉状保健品中豆甾醇、菜油甾醇、β-谷甾醇含量的分析方法。方法 保健品经过KOH和乙醇的皂化反应, 用乙酸调节pH至6.5~7.5, 使用C18色谱柱(100 mm×2. 1 mm, 1.8 μm), 甲醇为流动相, 等梯度洗脱, 用光电二极管阵列检测器在204 nm进行检测。结果 本方法可以在 10 min内完成3种植物甾醇的分离分析。3种植物甾醇线性范围为10~200 mg/L, 线性相关系数均大于0.99。豆甾醇、菜油甾醇、β-谷甾醇的检出限分别为0.095、0.13、0.13 g/100 g (S/N=3), 定量限分别为0.32、0.43、 0.44 g/100 g (S/N=10), 豆甾醇、菜油甾醇、β-谷甾低中高3种浓度的加标平均回收率分别为98.6%~102.9%、96.1%~101.9%和92.3%~98.7%, 6次重复性实验的相对标准偏差(relative standard deviation, RSD)均小于5%。结论 该方法快速、简便、准确、灵敏, 适合测定保健品中豆甾醇、菜油甾醇和β-谷甾醇的含量。     

加工过程对苹果籽油中植物甾醇流向分布影响

采用GC-FIR法对苹果籽加工过程中的植物甾醇进行了成分分析。结果表明,苹果籽油中植物甾醇主要成分为菜油甾醇、豆甾醇和β-谷甾醇,其中以β-谷甾醇含量最高;压榨法制备的苹果籽油植物甾醇的含量(385mg/100g)高于索氏提取(288mg/100g)和超声提取法(318mg/100g);且随着苹果籽油精炼程度提高,油脂中的有益微量成分植物甾醇损失增大。     

婴儿配方乳粉中4种植物甾醇的含量研究

目的气相色谱法分析我国市场上销售的30批次婴儿配方乳粉,研究其中的4种植物甾醇含量分布情况。方法样品中加入内标5-α胆甾烷醇溶液和10%乙酰氯甲醇溶液,在80℃水浴中甲酯化2 h,用甲苯萃取。加入碳酸钠溶液(6 g/100 mL)使其分层,取上层甲苯溶液氮吹浓缩后,定容至1.0 mL,用气相色谱仪分析。结果婴儿配方乳粉中4种植物甾醇含量在23.9～148.9 mg/kg之间,β-谷甾醇含量最高,分别占到各自乳粉中4种甾醇总量的40.9%～69.0%。结论此次检测的30批次婴儿配方乳粉中均含有一定量的植物甾醇,但样品中的甾醇含量不同。     

常见精练油中植物甾醇测定方法的建立及含量分析

为对我国常见的植物油中植物甾醇含量进行测定,建立了植物甾醇气相色谱分析方法,并对11类共25种精炼植物油中的β-谷甾醇、菜油甾醇、豆甾醇、β-谷甾烷醇、菜油甾烷醇及菜籽甾醇等的含量进行分析.本方法相对标准差为1.1%～6.9%;菜油甾醇、豆甾醇、β-谷甾醇的回收率的RSD值范围为3.0%～4.7%.玉米胚芽油中植物甾醇含量最高,其次是菜籽油和芝麻油.不同种类的植物油植物甾醇的含量和比例各不相同,同一种类不同品牌的植物油中各植物甾醇所占的比例基本接近.对我国居民植物油中植物甾醇的摄入量进行了初步估计.本研究建立的方法可靠,具有较高的准确度和精密度,可以作为精炼植物油中植物甾醇的测定方法.建议我国居民可以通过食用含植物甾醇较高的食用油来增加植物甾醇的摄入量。     

气相色谱法快速测定植物油沥青中的甾醇

建立了一种气相色谱法,用于快速测定植物油沥青中植物甾醇的组分和含量.方法中采用HP-5毛细管柱,FID检测器检测,内标法计算含量.甾醇在1～10mg/mL呈良好线性关系,植物油沥青中甾醇总含量为6.08%,包括菜油甾醇、豆甾醇和β-谷甾醇,回收率为96.2%～102.7%,相对标准偏差为1.54%.结果表明,该法操作简单、快速、准确.植物油沥青因富舍甾醇,具有很高的应用价值.     

米糠超临界流体萃取物中植物甾醇组分的气相色谱分析

用气相色谱法对米糠超临界流体萃取物中植物甾醇组成及其含量进行分析。结果表明：米糠超临界流体萃取物中含有3 种植物甾醇,即菜油甾醇、豆甾醇和β- 谷甾醇,其中β- 谷甾醇含量最高为8.47mg/g,其次是菜油甾醇含量为1.97mg/g,豆甾醇含量最低为1.23mg/g。气相色谱法检测米糠中植物甾醇种类及含量,可广泛用于植物原料中的植物甾醇的定性、定量分析。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.