烘烤条件对山核桃仁理化指标和挥发性成分的影响

为了探究烘烤条件对山核桃仁品质的影响,通过9组不同温度和时间组合的烘烤条件加工山核桃仁,分析其含水率、水分活度、颜色、甾醇、生育酚和挥发性成分的变化规律.随着烘烤时间和温度的增加,烘烤后的山核桃仁水分、水分活度、颜色和生育酚含量显著下降,而甾醇含量无显著变化.山核桃仁在160℃/26 min条件下烘烤的颜色最暗且生育酚...     

油脂饱和度对油炸马铃薯片品质的影响

以玉米油、花生油、大豆油、大豆棕榈调和油、棕榈油5种不同饱和度油脂作为煎炸用油,以马铃薯片为煎炸内容物,于140℃循环煎炸。考察马铃薯片的油脂含量、水分含量、色泽、酥脆性以及感官评分的变化,综合分析油脂饱和度对油炸马铃薯片品质的影响。结果表明:煎炸油脂的饱和度显著影响油炸马铃薯片的品质(p 0.05),随着煎炸油脂饱和度的增加,油炸马铃薯片的油脂含量呈降低的趋势,水分含量呈增加的趋势,L值呈增大的趋势,表明马铃薯片颜色随着煎炸油脂饱和度的增加而越发鲜亮;油炸马铃薯片的酥脆性、感官评分亦随煎炸油脂饱和度的增加呈显著增加的趋势(p 0.05)。由此可知,相对于不饱和度较高的玉米油、花生油、大豆油,饱和度较高的棕榈油更加适合马铃薯片的煎炸。     

食用油和脂防酸的介电特性

研究了食用油和脂肪酸的介电特性.油脂和脂肪酸的介电常数ε′在频率100Hz～500kHz之间显示了稳定性和最大值,从500kHz～1MHz显示了显著降低的趋势.脂肪酸的ε′随着双键的数量或分子链长度的增加而增加.油脂的ε′主要取决于C18不饱和脂肪酸的影响.结合偏最小二乘法(PLS)分析,介电分光图谱可以预测油脂中主要的脂肪酸成分.油脂的ε′随着温度增加而减少,随着水分含量的增加而增加.     

油炸温度和时间对外裹糊牡蛎品质的影响

以水分含量、油脂含量、颜色、感官评分和油脂吸收为指标,分别考察了油炸温度(165、175、185℃)和油炸时间(60、90、120、150、180 s)对油炸外裹糊牡蛎品质的影响。结果表明,随着油炸温度的升高和时间的延长,油炸外裹糊牡蛎的水分含量降低,油脂含量增加,L*值和b*值减小、a*值增大,感官评分先升高后下降,油脂吸收程度加大;175℃炸制90 s或120 s所得油炸外裹糊牡蛎色泽金黄,外酥里嫩,牡蛎特征风味突出,感官品质最好。     

水分含量对马铃薯淀粉凝胶体系脂肪吸收的影响

以马铃薯淀粉为原材料,与水进行模拟,在180 ℃条件下对马铃薯淀粉凝胶样品进行常压油炸,研究油炸样品中总油脂含量,以及各部分油脂含量的分布情况。结果表明：随着水分含量的增加,马铃薯淀粉凝胶体系油炸样品的总油脂含量、表面油脂含量和表面渗透油脂含量呈逐渐增加的趋势。随着油炸时间的延长,马铃薯淀粉凝胶体系油炸样品的总油脂含量和组织结构油脂含量呈逐渐增加的趋势,表面渗透油脂含量呈逐渐降低的趋势。随着水分含量的增加,表面渗透油脂含量在油炸样品总油脂含量中占据最大部分,其次是组织结构油脂含量,最少的是表面油脂含量。不同部分油脂含量的变化呈现一定的规律性,但变化幅度有一定的差异。     

综合指标评价鉴别餐厨废油脂的研究

通过测定各类食用植物油和餐厨废油脂的特征指标和品质指标,对其特征指标(折光指数、碘值和短链饱和脂肪酸)进行差异性分析,进行餐厨废油脂的初步鉴别;采用主成分分析法(Principal components analysis,PCA)以酸价、过氧化值、极性组分、金属元素含量和反式脂肪酸含量为主要品质指标对各类油脂进行分析,从5个影响油脂品质的指标中提取3个主成分构建数学评价模型,通过各类油脂的主成分得分鉴别餐厨废油脂。研究表明,餐厨废油脂的特征指标与各类食用植物油存在显著性差异;利用评价模型计算出各类油脂在各主成分的得分,3个餐厨废油脂样品的主成分综合得分比普通食用植物油高,油脂总体品质恶劣,表明综合指标评价鉴别餐厨废油脂是可行的。     

玉米胚芽水分含量对其油脂品质的影响

研究了玉米胚芽水分含量对其油脂品质的影响。通过调整玉米胚芽中水分含量,提取其中油脂,研究玉米胚芽水分含量变化对其油脂脂肪酸组成、理化指标、主要有益微量伴随物的影响。结果表明:玉米胚芽水分含量变化对其油脂脂肪酸组成和甾醇含量基本没有影响,但随着玉米胚芽水分含量提高,其油脂酸值、过氧化值、色泽都会升高,生育酚含量下降,并且α-生育酚和γ-生育酚含量变化与玉米胚芽油色泽红值具有良好的相关性。     

淡水养殖珍珠的化学成分与呈色机理研究

将淡水养殖珍珠按颜色分类, 通过傅里叶变换红外光谱、等离子发射光谱、拉曼光谱和X射线粉末衍射等对其进行了有机成分和无机成分的测试研究, 发现珍珠的颜色主要受微量金属元素和类胡萝卜素的影响.     

卡尔费休法在油脂水分测定中的应用

用恒温烘箱和真空烘箱方法测定油脂水分含量,测定时间较长,操作繁琐,需要一种快速检验方法来代替.通过卡尔费休法与国标方法在油脂水分测定中的比较,结果卡尔费休法测定油脂水分能取得与国标法相近的结果,且重现性好,操作方便快捷,可以推广使用.     

微波处理油料对油脂品质影响的研究进展

介绍分析了微波处理油料对出油率、原料本身结构、油脂主要理化指标、油脂脂肪酸组成及微量成分和油脂氧化稳定性的影响.结果指出微波处理油料可提高出油率和油脂氧化稳定性,增加营养成分含量,值得推广应用.     

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.     

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.     

Detection of adulteration of locust bean gum with guar gum by capillary electrophoresis and polarized light microscopy

Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH₃CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH₂PO₄-20.6 mM Na₂B₄O₇ buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.