远红外处理延缓松花粉脂质的氧化作用

以松花粉为原材料,研究远红外加热对其杀菌效果、灭酶效果、脂质氧化性能和营养品质的影响,并分析了灭菌破壁松花粉在加速氧化过程中色泽、过氧化值和挥发性成分的变化。结果表明,远红外加热可显著降低松花粉中微生物含量,且加热温度越高,作用时间越长,灭菌效果越显著。松花粉在100℃加热15 min或110℃加热10 min即可达到灭菌要求,此时,脂肪酶灭活率、类胡萝卜素损失率、游离脂肪酸含量和过氧化值分别为55.21%、40.67%、1.95 mg/kg、0.46 meq/kg或61.65%、39.83%、2.27 mg/kg、0.45 meq/kg;此外,在此作用条件下,松花粉的基本组成成分和氨基酸含量未发生明显损失。在加速氧化过程中,远红外灭菌破壁松花粉(FI-100-15和FI-110-10)的色泽未发生明显变化,过氧化值、己醛和己酸含量略有增加,但变化趋势较小。表明在100℃加热15 min或110℃加热10 min的作用条件下,远红外灭菌不仅可有效杀灭松花粉中的微生物,还可延缓脂质氧化速度,提高其储藏稳定性,是一种潜在的松花粉灭菌方式。     

电子束辐照对松花粉脂质氧化及其品质的影响

以原松花粉为试材,研究电子束辐照对其杀菌效果、脂肪酶活力、脂质氧化性能和营养品质的影响,并分析了破壁松花粉在加速氧化过程中色泽、过氧化值和挥发性成分的变化。结果表明,电子束辐照可显著降低松花粉中微生物含量,且辐照剂量越大,杀菌效果越显著;菌落总数、霉菌酵母数和大肠菌群的D10值分别为2.20、1.95和1.84 kGy;随着辐照剂量的增加,松花粉中脂肪酶活力、类胡萝卜素含量和游离脂肪酸含量显著降低,过氧化值略有升高但总体仍处于较低水平,当辐照剂量为8 kGy时,脂肪酶灭活率为53.52%,类胡萝卜素保留率为60.81%,游离脂肪酸含量为1.38 mg/kg,过氧化值为0.46 meq/kg;此外,8 kGy剂量辐照对松花粉的基本营养成分及氨基酸含量无明显影响,在加速氧化过程中,破壁松花粉的色泽无明显变化,过氧化值、己醛和己酸含量增幅不大。表明8 kGy电子束辐照对松花粉营养品质影响不大,并能有效杀灭微生物,抑制脂质氧化,提高产品储藏稳定性。     

顶空气相色谱法测定兔肉中挥发性风味物质己醛和己酸

为测定兔肉中挥发性风味物质己醛和己酸的含量,建立了基于顶空气相色谱法的兔肉中挥发性风味物质己酸和己醛的检测方法。品在静态顶空70℃条件下平衡20 min进样,用Rtx-Wax色谱柱升温分离,FID检测,以保留时间定性,外标法定量。结果表明,己酸和己醛在5~100μg/kg内均线性关系良好,相关系数分别为0.999 3和0.999 5。该方法下己酸和己醛的检出限分别为1.49μg/kg和2.57μg/kg,定量限分别为4.5μg/kg和7.78μg/kg。加标回收试验表明,己醛的加标回收率为89%~98%,相对标准偏差为3.81%;己酸的加标回收率为90%~96%,相对标准偏差为2.41%。兔肉中挥发性风味物质己醛检出量为49.62~67.73μg/kg;己酸检出量为10.32~14.92μg/kg。OAV分析表明己酸和己醛对兔肉腥味有直接影响。     

葡萄籽油和亚麻籽油储藏期间氧化对功能性成分影响

通过实验研究35℃恒温避光储藏亚麻籽油和葡萄籽油过氧化值、p–茴香胺值、脂肪酸组成和维生素E含量变化,探讨储藏期间油脂氧化劣变对其功能性成分影响。结果表明,经60天储藏,葡萄籽油、亚麻油过氧化值分别达241.30 mmol/kg、248.72 mmol/kg;p–茴香胺值为32.20、104.06;油脂脂肪酸组成不饱和脂肪酸减少0.35%和0.41%,亚油酸和亚麻酸分别降低0.20%和0.09%、0.23%和1.04%,反式脂肪酸含量基本没有变化;维生素E含量显著降低均未检出;储藏期间亚麻籽油氧化对功能性成分影响均大于葡萄籽油。     

新鲜薏仁米与异味薏仁米挥发性成分对比分析

以新鲜薏仁米和异味薏仁米为原料,采用顶空—固相微萃取—气质联用法分别对新鲜薏仁米和异味薏仁米的挥发性成分进行分析。研究结果表明:从新鲜薏仁米和异味薏仁米中共鉴定出85种挥发性成分,其中新鲜薏仁米中鉴定出47种化合物(主要包括12种醇类、11种醛酮类、22种烃类),其主要挥发性成分为右旋萜二烯、苯、2-戊基呋喃、己醛、壬醛、正辛醛、2-庚酮、正戊醇、正己醇、1-辛烯-3-醇和芳樟醇;异味薏仁米中鉴定出58种化合物(主要包括17种烃类、8种醇类、14种醛酮类、10种酯类和5种酸类),其主要挥发性成分为1-十五烯、己醛、壬醛、癸醛、正辛醛、正辛醇、己酸、庚酸、辛酸和壬酸。造成新鲜薏仁米与异味薏仁米的主要挥发性成分中酸类化合物种类和含量差异的主要原因,可能是新鲜薏仁米在贮藏过程中油脂的氧化。     

桑椹多酚对广式腊肠贮藏过程中脂质降解和氧化特性的调控作用

脂质氧化和水解是形成腊肠特征风味的重要途径,但过度氧化会造成腊肠品质的劣变。桑椹多酚是一类天然抗氧化剂,被证实可以有效缓解腊肠储藏过程中的氧化反应,然而其通过调控腊肠脂质氧化和水解来改变腊肠风味的相关机制还鲜有研究报道。鉴于此,该研究将桑椹多酚提取物（1 g/kg）加入到肉糜中,制成广式腊肠,跟踪28 d的储藏过程中腊肠的脂质氧化代谢产物（共轭二烯、共轭三烯、TBARS和己醛）以及脂肪酸（中性脂肪酸、游离脂肪酸和磷脂）的组成变化。研究发现,桑椹多酚主要通过抑制脂质次级代谢产物（己醛和丙二醛）来延缓腊肠的脂质氧化。经过28 d的储藏期后,桑椹腊肠中己醛与丙二醛的含量较对照组分别下降63.10%与28.05%。此外,储藏过程中桑椹多酚还可以有效抑制腊肠储藏过程中游离脂肪酸、磷脂的释放。经过28 d的储藏期后,与对照组相比,桑椹腊肠的游离脂肪酸含量下降了9.59%。同时,桑椹多酚还可以减少风味物质中醛类物质的产生和积累。综上所述,桑椹多酚主要通过延缓腊肠储藏过程中脂质的降解及次级氧化过程来调控产品的风味。     

烹饪方法对兔排油脂氧化和挥发性呈味物的作用研究

本文对比研究了煎、炸、微波和烤4种中式烹饪方式处理的兔排脂质氧化程度和挥发性呈味物的异同与联系。烹饪导致兔排油脂氧化,以微波和烤制样品的TBARs值升高最为显著(P0.05),分别达到1.31 mg MDA/kg样品和1.23 mg MDA/kg样品。烹制兔排样品中共检测出56种挥发性化合物,不同烹制方式导致兔排中各挥发性化合物含量存在一定差异;烤兔排的总挥发性化合物含量最高。新鲜兔排挥发性化合物的主成分是酯类,而醛类是烹饪样品中挥发性化合物的主成分,在煎制、油炸、微波和烤制兔排样品中醛类化合物分别占据总挥发性化合物的54.31%、53.21%、59.99%和65.19%。兔排油脂氧化指数TBARs值与挥发性化合物中总酯类含量呈线性负向相关,与总醛类、总呋喃类及总挥发性化合物含量呈正相关,其中与己醛的相关系数高达0.793,说明油脂氧化产物是烹制兔排挥发性化合物的主成分物来源。     

鱼油氧化稳定性研究—感官及理化参数评价

目的:研究鱼油样品在储藏过程中氧化指标(游离脂肪酸含量、过氧化值、挥发性二级氧化产物含量)和感官属性之间的关系,以更好地监控鱼油的质量。方法:通过加速储藏实验,将2种鱼油样品(花生四烯酸、二十二碳六烯酸)于40℃避光储藏30d,每天监控检测其感官属性(香气)、游离脂肪酸含量、过氧化值及挥发性二级氧化产物(己醛及丙醛)的含量。以感官评价结果为判定依据,研究各理化指标与鱼油氧化程度的关系。结果:2种油脂样品中的游离脂肪酸含量在储藏过程中无明显变化,不是一个可以评价油脂货架期内氧化程度的有效指标。过氧化值的测定结果显示,此指标可以反映油脂初期氧化的趋势,但不能很好地反映油脂感官属性的变化。挥发性二级氧化产物的测定结果与油脂感官属性的变化显示了高度的一致性,能够很好地反映油脂氧化状态。结论:在不具备感官评价条件的情况下,建议同时监测鱼油中挥发性二级氧化产物(ω-6脂肪酸监测己醛;ω-3脂肪酸监测丙醛)及过氧化值的含量,以更全面有效地评价鱼油的氧化状态,更好地控制鱼油的质量。     

顶空-固相微萃取-气相色谱-质谱联用结合嗅闻法分析异味薏米的异味成分

采用顶空-固相微萃取-气质联用法(HS-SPME-GC-MS)分别对新鲜薏米、弱异味薏米和强异味薏米的挥发性成分进行分析,从3种不同异味程度的薏米中共鉴定出79种挥发性成分,新鲜薏米、弱异味薏米和强异味薏米中分别鉴定出47、43和51种挥发性成分,相对百分含量分别为96.14%、98.68%和98.00%。通过对比上述3种不同异味程度的薏米中挥发性成分的种类和含量,同时应用气相色谱-质谱联用结合嗅闻(GC-O-MS),采用气味活度值(OAV)结合气味强度值对强异味薏米中的异味成分进行鉴定。从强异味薏米的挥发性成分中鉴定出12种异味成分,分别为己醛、庚醛、2-庚烯醛、辛醛、反-2-辛烯醛、壬醛、反-2-壬烯醛、癸醛、2-癸烯醛、己酸、2-壬酮和6-十一酮。     

玉米储藏过程中挥发性成分变化研究

为了研究玉米储藏期间气味变化情况,采用优化的顶空固相微萃取-气质联用法(HS-SPME-GC-MS)分析玉米在常温(25℃)密闭储藏过程中的主要挥发性成分组成。检出的物质主要包括烃类、醛类、酯类、醇类、酮类、酸类和少量杂类物质。结果表明,在储藏过程中烃类物质总相对含量在储藏末期比储藏初期有所增加。酸类物质相对含量呈缓慢上升但含量较低。酮类物质相对含量较低且呈逐渐降低趋势。醇类挥发性成分在储藏120 d前呈现增加趋势,在120 d后有所降低。醛类和酯类物质相对含量呈现先升高后降低,二者相对含量较高,储藏180 d后的相对含量接近于0 d,是玉米风味的主要贡献物质。而烃类和醇类风味阈值较高,不是玉米储藏期间风味的主要贡献物质。25℃下密闭储藏180 d后的玉米其气味与储藏0 d的玉米相比,并未发生人嗅觉可感知的明显异味变化。     

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.     

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.     

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.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the