预处理对低温压榨花生油风味物质的影响

采用顶空固相微萃取(HS-SPME)和气相色谱–质谱联用(GC-MS)技术检测不同预处理低温压榨花生油中挥发性风味物质,探讨不同预处理低温压榨花生油中醛类、酮类、吡嗪类等挥发性风味物质的种类和相对含量。结果表明:被检测的花生油样品中共鉴定出97种挥发性风味物质,不同预处理方式制得的低温压榨花生油其挥发性风味物质差异很大。脉冲电场预处理低温压榨花生油主要呈味物质为3-羟基-2-丁酮;微波预处理低温压榨花生油挥发性风味物质以吡嗪类和吡咯类物质居多;超声波预处理低温压榨花生油挥发性风味物质主要是酸类。预处理方式对低温压榨花生油挥发性风味物质的影响有显著差异,不同预处理方式可以获得不同风味的低温压榨花生油。     

不同压榨工艺下花生油风味成分的变化

该研究采用顶空固相微萃取-气相色谱-质谱联用仪（HS-SPME-GC-MS）及电子鼻对不同压榨工艺下花生油挥发性风味成分和脂肪酸组成进行分析。6种不同压榨工艺花生油中共检测到10类38种挥发性成分,其中包含19种风味成分。在热榨花生油中以呋喃类（63.43%~66.68%）、醛类（10.04%~5.47%）、酚类（8.83%~7.18%）为主要的挥发性成分,在冷榨花生油中以酯类（26.43%）、醛类（23.47%）、酸类（22.10%）为主要的挥发性成分。此外,热榨花生油检测出少部分吡嗪、吡啶、酮类关键风味成分,其在冷榨花生油中并没有检出。电子鼻结果基本与GC-MS一致,硫化物、芳香化合物、氮氧化合物和甲基类化合物对花生油整体风味贡献率较大,通过主成分分析和K-mean聚类分析结果显示6种花生油挥发性成分变化差异显著。6种花生油脂肪酸组成都以油酸、亚油酸、棕榈酸为主,含量可达到90%以上。然而通过对比不同温度下花生油脂肪酸组成发现随着压榨温度的升高,不饱和脂肪酸的氧化加速。综上,对比不同压榨工艺下花生油风味和营养成分的变化发现高温条件压榨下花生油的风味成分显著增加,花生油品质略有下降,利用电子鼻可快速区分不同压榨工艺花生油。     

基于气相色谱-离子迁移谱法分析花生油中挥发性风味成分

目的 基于气相色谱-离子迁移谱(gas chromatography-ion mobility spectrometry, GC-IMS)技术建立花生油挥发性风味品质判定方法。方法 以7个厂家的198个花生油样品为研究对象, 采用GC-IMS技术对不同厂家、不同工艺的花生油样品的挥发性有机物(volatile organic compounds, VOCs)组成进行分析。利用指纹图谱及动态主成分分析(principal component analysis, PCA)研究不同工艺对花生油挥发性风味品质的影响, 分析不同厂家花生油产品的调制情况。结果 共检出花生油中74种VOCs, 选取了花生油中响应强度共性较高的吡嗪类、呋喃类、糠醛类、噻唑类等15种挥发性物质进行深入分析, 其指纹图谱与PCA结果表明, 不同厂家及工艺的花生油有自己独特的挥发性风味成分, 组内聚类簇明显, 风味轮廓相似, 表明加工工艺稳定性较好; 组间无明显交叉, 风味轮廓界限分明。但花生油风味并不能简单地按照工艺来区分, 厂家加工工艺间的差异将导致VOCs种类和含量的不同。结论 GC-IMS可实现花生油挥发性风味品质简便、快速、准确、灵敏科学测定, 该研究能够为厂家产品工艺优化和油脂品质加工提供理论依据。     

热处理方式对低温压榨花生饼风味的影响

采用顶空固相微萃取和气相色谱-质谱联用技术对微波烘烤和烘箱烘烤处理的6个低温压榨花生饼样品风味进行分析,并对鉴定的挥发性风味成分进行主成分分析(PCA)和聚类分析(CA),以便对各样品的风味相似性进行明确评价。结果表明:从6个样品中共鉴定出91种挥发性风味物质,包括醛类(10种)、酮类(4种)、醇类(6种)、烃类(4种)、酚类(5种)、吡嗪类(25种)、呋喃类(9种)、吡咯类(7种)、吡啶类(7种)及其他(14种);烘箱烘烤处理的低温压榨花生饼中醛类、醇类物质的相对含量较高,而微波烘烤处理更有利于吡嗪类、吡咯类、吡啶类、呋喃类等含氮氧杂环化合物的形成;采用PCA和CA可以区分不同加热处理的低温压榨花生饼风味,其中烘箱160℃烘烤15 min、烘箱170℃烘烤15 min和540 W微波2 min样品的风味轮廓相似度较高,540 W微波3 min、烘箱180℃烘烤15 min和540 W微波4 min样品风味较相似,此外PCA与CA结果一致,可相互验证。     

花生炒籽工艺条件与小榨花生油风味品质的相关性研究

为制备风味品质较优的小榨花生油,在不同炒籽条件下处理花生仁,压榨制备小榨花生油。对小榨花生油进行感官评价,基于主成分分析(PCA)分析炒籽条件与小榨花生油风味类型的相关性,并对小榨花生油风味物质含量进行了测定。结果表明：炒籽温度低于160℃时小榨花生油呈生香味、甜香味,风味弱,在炒籽温度160～165℃时呈甜香味、熟坚果味,在炒籽温度170℃时开始表现出煳味,并且随着炒籽温度的升高煳味增大;当入炒水分由4.09%升高到7.12%时,小榨花生油的风味类型没有明显改变,风味强度略有增加;在炒籽温度145～160℃条件下,醛类和吡嗪类化合物为主要呈味物质,在炒籽温度165℃以上时,吡嗪类化合物是最主要的呈味物质,并且随着炒籽温度的升高,吡嗪类化合物占比呈现逐渐增加趋势,醛类化合物占比呈现逐渐降低趋势;在入炒水分4.09%和7.12%、炒籽温度145～175℃条件下,风味物质总量分别为15.7～43.2 mg/kg和11.5～39.8 mg/kg。综上,选择165℃的炒籽温度,可得到具有较好风味品质的小榨花生油。     

植物油加工工艺对风味物质影响的研究进展

风味是植物油品质的重要特征之一,除与油料本身有关外,还与加工工艺密切相关。不同加工工艺生产的植物油风味物质在种类和含量上存在差异。综述了植物油风味物质产生的机理、不同加工工艺（烘烤、微波预处理、红外辐射、压榨法、溶剂浸出法、水酶法、超临界萃取法、亚临界萃取法和精炼等）对植物油风味物质影响的研究进展,并对目前食用植物油在风味研究方面存在的问题进行了探讨,旨在为风味植物油的生产提供一定的参考。     

不同方法提取的花生油品质分析研究

通过对冷榨(压榨温度60℃)、低温压榨(压榨温度80℃~90℃)、高温压榨(压榨温度120℃以上)以及浸提4种不同方法制得的花生油的主要理化指标、脂肪酸组成、VE含量及氧化诱导时间的测定,分析比较不同方法制油对花生油品质的影响。结果表明:不同花生制油工艺所得的花生特征指标(碘值、皂化值和折光指数)差异不明显,花生油的质量等级指标(酸值、过氧化值、色泽和风味)差异明显。浸提精炼花生油的酸值、过氧化值、色泽都优于压榨花生油,但香味最淡;压榨花生油的VE含量和氧化诱导时间都显著优于浸出精炼花生油。不同制油工艺所得花生油的主要脂肪酸组成相差很小,但冷榨花生油中亚油酸和亚麻酸含量高于浸提油、高温压榨油及低温压榨油,浸提精炼花生油中亚油酸含量明显低于压榨花生油。浸提精炼花生油中发现反式脂肪酸。     

生产工艺对压榨芝麻油风味的影响

为了在提高芝麻油风味的基础上降低生产成本,探究生产工艺各阶段对压榨芝麻油风味的影响。对芝麻油生产过程中的原料水洗、调质、压榨、水化脱胶、过滤等阶段进行研究,采用感官评价和仪器检测相结合的方式对芝麻油的风味进行测定。结果表明：芝麻原料水洗后得到的芝麻油风味物质含量增加30.44%,且风味更加浓郁纯正;在芝麻炒籽、扬烟后进行调质处理,芝麻油风味物质含量比不调质增加34.26%,风味更加浓郁,口感润滑;在芝麻榨油时进行多段压榨,前段压榨芝麻油的风味物质含量比后段压榨芝麻油的增加43.15%,且前段压榨芝麻油风味更加纯正,口感爽滑细腻;自然沉降的芝麻油风味物质含量比水化脱胶芝麻油的增加20.35%;添加0.5%的珍珠岩过滤后,芝麻油风味物质含量降低14.13%,添加0.5%的干饼粉过滤的芝麻油风味物质含量降低7.31%。综上,对芝麻原料进行水洗处理,炒籽、扬烟后进行调质处理,分段压榨取油,对芝麻原油进行低温自然沉降处理,以及减少水化脱胶加水量,尽量不添加或者少添加助滤剂,可显著提高芝麻油的风味。     

五种制油工艺对花生油风味物质种类的影响

为了探究不同制油工艺对花生油风味物质种类的影响。通过顶空固相微萃取(HS-SPME)和气相色谱-质谱联用技术(GC-MS)检测市售的古法、冷榨和热榨花生油与自制的未烘烤和烘烤水酶法花生油的挥发性风味物质,对比分析不同制备工艺对其挥发性风味物质的影响。结果表明:古法、冷榨、热榨、未烘烤水酶法和烘烤水酶法测得的花生油的挥发性物质种类分别为41、39、41、56和56种,水酶法制备的花生油挥发性风味物质种类最多。根据各种物质相对含量分析,发现醛类物质在五种花生油中种类及相对含量均较高,对其风味的影响均较大;醇类物质主要存在于冷榨和未烘烤水酶法制备的花生油;吡嗪类和含苯环类物质主要存在于古法、热榨和烘烤水酶法制备的花生油中,对其风味有较大贡献;酯类物质主要对古法压榨和未烘烤水酶法制备的花生油风味有一定的影响;酸类物质在热榨和烘烤水酶法制备的花生油占比较高,对其风味影响较大;酮类、醚类、烷烃类、烯烃和炔烃类物质占比较小,并且呈味阈值高,对五种花生油的风味贡献均较低。     

不同方法提取的花生油对煎炸三文鱼风味成分的影响

本实验目的是研究花生油对煎炸三文鱼风味的影响,采用顶空固相微萃取-气相色谱质谱联用(HS-SPME-GC-MS)技术,比较用水媒法和压榨法得到的6种花生油煎炸三文鱼后对其挥发性风味组分的影响。结果表明:经6种花生油煎炸后,三文鱼中的挥发性风味物质均明显增多,共检测出87种挥发性物质,主要为醛类、醇类和烃类(烷烃、烯烃、芳香烃),以及含氮杂环吡嗪类等。其中醛类数量增加最为明显,其次是醇类物质。而烃类物质种类数量变化不大,但6种样品中烃类物质的相对含量平均下降了60.41%。6种花生油煎炸后的挥发性成分中均检测到吡嗪类化合物。利用富含吡嗪类化合物的花生油煎炸三文鱼时,由于其本身带有的吡嗪类化合物易挥发,大部分在高温煎炸过程中损失,并不能赋予煎炸三文鱼特殊的烤花生风味。两种提取方法得到的6种花生油,煎炸三文鱼时得到的主体挥发性物质种类及其相对含量相似,差别较小。     

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.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status