不同提取工艺对产油酵母油脂产率的影响

研究了不同的油脂提取工艺对产油酵母油脂产率的影响。以高产油酵母JM-D为原料,以油脂产率为测定指标,比较了蜗牛酶法、超声波破碎法、反复冻融法、细胞匀浆机破碎法、微波破碎法、研磨法以及酸热法对酵母细胞壁的破碎效果,并对有机溶剂提取法与索氏抽提法提取细胞内油脂的效果进行比较。结果显示,蜗牛酶法的细胞破碎效果最好,油脂产率高达46.2%;其次是反复冻融（100℃水浴解冻）法,油脂产率高达43.4%;研磨法+酸热法的油脂提取效果也较好,油脂产率达到37.8%。研磨后,采用索氏抽提法的提取效果优于有机溶剂提取法的。     

植脂末中脂肪测定方法研究

<正>分别使用脂肪测定中常用的索氏提取法、酸水解法、碱水解法对植脂末中脂肪测定进行了对比研究,并且对乙醚和石油醚的提取效果进行了研究,实验结果表明索氏提取法和碱水解法不适合植脂末中脂肪的测定,酸水解法可以作为植脂末脂肪测定的推荐方法,石油醚(30℃~60℃)完全可以替代乙醚作为植脂末脂肪测定的提取溶剂。     

从微藻中提取粗脂的方法比较

采用改良的酸水解法、异丙醇法、乙醇法、乙醚-石油醚法、索氏抽提法5种方法对3株微藻的粗脂含量进行测定。结果表明,改良的酸水解法与索氏抽提法提取效果稳定、粗脂提取程度高。与索氏抽提法相比,改良的酸水解法大大节省了测定时间,且可以同时对多个样品进行测定,是实验室中对多个微藻样品粗脂含量快速测定的首选方法。     

啤酒酵母油脂的超高压提取

采用单因素实验和正交实验方法研究溶剂、液固比、压力和处理时间对酵母油脂提取率的影响,探讨超高压处理对啤酒酵母油脂提取的工艺条件,并对确定的最佳提取条件进行验证,以GC-MS法分析酵母油脂的主要成分。结果表明,以20倍(v:m)95%的乙醇为溶剂,在400MPa的压力下提取7min时,酵母油脂的提取率最高,为3.7469%,为索氏提取法测得的酵母油脂含量的72.11%。所得油脂中,总脂肪酸占45.87%,其中不饱和脂肪酸占34.90%,中性脂占46.84%,磷脂占总油脂含量的7.25%。不饱和脂肪酸以油酸、棕榈油酸和亚油酸为主占大多数。由此说明,超高压提取技术可应用于酵母油脂的提取加工,其提取时间明显缩短,但提取率略低于索氏提取法。酵母油脂的不饱和脂肪酸含量较高,可用于医药保健品的开发。     

桔核油脂中脂肪酸的组成分析

采用索氏提取法对桔核中的油脂进行提取,然后将油脂进行皂化、甲酯化,以毛细管色谱-质谱联用法(GC-MS)测定桔核油脂中的脂肪酸组成,共鉴定出11种成分,主要含有亚油酸、油酸、棕榈酸、硬脂酸和亚麻酸,其含量分别为34.17%,28.25%,19.30%,7.41%和7.15%.     

测定食品脂类的几种常用方法

本文简要介绍了测定食品脂类含量的几种常用方法,对索氏抽提法(索克列特抽提法)、酸水解法、罗紫-哥特里法(碱性乙醚法)和氯仿-甲醇提取法四种方法的操作注意事项进行了说明.指出在实际食品检验工作中,应根据不同的样品特点选择适当、合理的检验方法,提高油脂含量的检测精度.     

酸水解法与索氏抽提法测定火腿肠中脂肪含量的比较研究

采用酸水解法和索氏抽提法测定火腿肠中的脂肪含量,结果表明,酸水解法和索氏抽提法检测样品中脂肪的含量分别为12.05g/100g、11.91g/100g,通过t值检验得知,两种方法无明显差异,但由于索氏抽提法的相对误差和变异系数比酸水解法的值小,因此,索氏抽提法的准确度和精确度较高。     

酸浆果籽油的提取研究

研究浸泡法、超声波辅助萃取法和索氏萃取法对黑龙江产酸浆果籽萃取的影响,分别对乙酸乙酯,乙醚和正己烷的提取效果进行比较.结果表明,浸泡法的籽油产率为乙酸乙酯的18.68%、乙醚的17.68%以及正己烷的14.30%;超声波辅助萃取法的油脂产率为乙酸乙酯的18.51%、乙醚的19.55%以及正己烷的17.26%;索氏提取法的油脂产率为乙酸乙酯的19.53%、乙醚的19.70%以及正己烷的18.83%.GC-MS分析表明3种方法获得的果籽油成分均以亚油酸和油酸为主.     

酸水解法与自动索氏抽提法测定人造奶油脂肪含量的差异研究和方法改进

采用酸水解法和自动索氏抽提法测定6种不同人造奶油试样的脂肪含量,并对自动索氏抽提法进行改进,对不同方法的结果差异进行分析和研究。结果表明:酸水解法的实验结果偏低;且酸水解法和自动索氏抽提法对人造奶油脂肪含量的测定存在显著差异,采用自动索氏抽提法更合适。同时,对自动索氏抽提法进行改进,实验结果准确度高,其标准差为0.12,均值标准误差为0.03,说明改进自动索氏抽提法重现性好;且改进法对实验具有显著的影响。采用改进自动索氏抽提法,抽提纸筒可循环使用12次,有效降低了实验成本。     

新疆胡萝卜籽油脂肪酸GC-MS分析

采用索氏提取法从两种新疆胡萝卜籽中提取油脂,并通过GC-MS对两种胡萝卜籽油中的脂肪酸组成及其相对含量进行了分析.结果表明:两种胡萝卜籽油中脂肪酸组成主要为油酸、亚油酸、棕榈酸、硬脂酸,其不饱和脂肪酸含量较高,且油酸含量超过75％.     

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