酶促酯交换对棕榈硬脂基塑性脂肪甘三酯组成及物理性能的影响

利用脂肪酶Lipozyme TLIM催化棕榈硬脂(PS)与大豆油(SO)(PS∶SO分别为9∶1,8∶2,7∶3,6∶4,5∶5,wt%)酯交换反应,研究酯交换反应前后混合油脂体系中甘三酯组成的变化及其与油脂物理性能的关系。结果发现,酯交换后油脂中PPP、LLL、POP、PPL、PLL、PLO六种甘三酯含量发生明显变化,其中PPP、LLL含量下降,PPL、PLL、PLO含量增加,而POP除9∶1外,其含量均下降;SSS(S代表饱和脂肪酸)和UUU(U代表饱和脂肪酸)型甘三酯含量下降,而SUU和SUS含量增大,导致油脂熔点和固体脂肪含量(SFC)均不同程度下降,从而可制备不同SFC要求的塑性脂肪。PS∶SO为7∶3、6∶4、5∶5时,酯交换后油脂β'晶型增多,可为人造奶油、速冻专用油脂等塑性脂肪提供理想晶型。     

新型中长链甘三酯的制备及其在人造奶油中的应用

以全氢化高芥酸菜籽油(HERO),中链甘三酯(MCT)和棕榈油(PO)的混合油样为原料油,化学法酯交换合成低热量中长链甘三酯(MLCT)。研究了化学酯交换前后混合油样的甘三酯组成、固体脂肪含量及热学性质的变化,并对酯交换产品进行应用测试分析。结果表明:酯交换改善了混合油样的甘三酯组成、固体脂肪含量及热学性质,该酯交换产品可用于人造奶油中。     

不同部位猪油品质特点的比较

针对不同部位猪膘,测定其脂肪含量及对应猪油的熔点、碘值、固体脂肪含量(Solid fat content,SFC)、脂肪酸组成和甘三酯组成,并结合感官评价,对猪油进行香味的比较,结果表明:前腿膘的脂肪含量最高,为(88.18±0.21)%,花膘脂肪含量最低,仅为(64.31±0.69)%。猪油的熔点范围在(27.5~48.4)℃之间,以花膘油的熔点最高、前腿膘油的熔点最低。SFC曲线表明花膘油、网膘油的SFC曲线较为陡峭,可塑性较差,板油、背膘油、碎膘油的可塑性较好。脂肪酸组成测定结果为猪油的脂肪酸主要包括油酸、棕榈酸、亚油酸和硬脂酸,其中花膘油的硬脂酸和棕榈酸最高、背膘油中油酸含量最高,前腿膘油中亚油酸含量最高,与植物油不同的是,猪油含有少量的奇数碳脂肪酸。猪油的甘三酯成分分析表明,猪油的主要成分为OPO、SPO和LPO,3种甘三酯的总和占50%,Sn-2位置上主要以棕榈酸为主,不饱和脂肪酸主要集中在Sn-1,3位置上,感官评价不同部位猪油的香味,以板油和网膘油的焦糊味较浓、背膘油的猪肉特征香味较浓,而花膘油的油腻味、腥膻味、刺激味较浓,不宜食用。通过不同部位猪油的品质特点比较,为猪油的合理利用提供了参考。     

基于酶促酯交换的速冻专用油脂制备及应用研究

利用脂肪酶Lipozyme TL IM催化质量比为7:3的棕榈硬脂与大豆油进行酯交换反应,混合油脂中的高熔点甘三酯三棕榈酸甘油酯(PPP)的含量从27.61%降至9.50%。以酯交换油为主体,设计了5种不同塑性范围和固体脂肪含量的基料油,并以此基料油为原料制备出5种速冻专用油脂,然后将之应用于制作速冻汤圆。结果表明,当基料油中的油脂配比为酯交换油:大豆油:棕榈硬脂=84:13:3(wt%)时,所制备的专用油脂具有最佳的抗冻性能,以之制作的速冻汤圆冻裂率最低,仅为5%,而应用市售速冻专用油脂、未酯交换油脂制备的速冻专用油脂、未添加速冻专用油脂制作的的汤圆冻裂率分别为30%、20%和50%;此外,所得速冻汤圆表面细腻,光洁,有弹性,口感好,感官评分最高,表明通过酶促酯交换反应可以制备出品质优良的速冻专用油脂。     

巧克力涂层基料油理化性质和相容性的研究北大核心CSCD

选用棕榈油中间分提物(PMF)和氢化棕榈油(HPO)作为巧克力涂层的基料油,对两种油脂的理化性质进行了分析。同时,通过等温曲线和实测固体脂肪含量与理论固体脂肪含量的偏差曲线分析PMF和HPO的相容性。实验结果表明:PMF和HPO在脂肪酸和甘三酯的组成上相似,PMF和HPO具有良好的相容性,PMF和HPO按照比例3∶7(质量比)混合可以作为巧克力涂层基料油配方。     

巧克力涂层基料油理化性质和相容性的研究

选用棕榈油中间分提物(PMF)和氢化棕榈油(HPO)作为巧克力涂层的基料油,对两种油脂的理化性质进行了分析。同时,通过等温曲线和实测固体脂肪含量与理论固体脂肪含量的偏差曲线分析PMF和HPO的相容性。实验结果表明:PMF和HPO在脂肪酸和甘三酯的组成上相似,PMF和HPO具有良好的相容性,PMF和HPO按照比例3∶7(质量比)混合可以作为巧克力涂层基料油配方。     

棕榈仁油干法分提工艺实践

为开发代可可脂系列产品,介绍了采用油盘冷房结晶-高压膜压滤机过滤的精炼棕榈仁油干法分提生产棕榈仁硬脂工艺。对该工艺操作控制要点进行了说明,并对生产中的一些问题进行了讨论,将该工艺制备的棕榈仁硬脂及其氢化硬脂与天然可可脂和商业氢化棕榈仁硬脂代可可脂产品质量进行了对比。原料油主要质量指标为酸值(KOH)≤0.3 mg/g、碘值(I)16～19 g/100 g、熔点25～28℃和固体脂肪含量(25℃)≥18%。适合的工艺条件为预冷温度29～30℃,预冷时间3 h,冷房温度17～19℃,冷房结晶时间6～8 h,油结晶温度25～27℃,过滤压力0～0.3 MPa、挤压压力1.6～1.8 MPa。产品主要质量指标为酸值(KOH)≤0.3 mg/g、碘值(I)5.6～7.5 g/100 g、熔点30～34℃、固体脂肪含量(30℃) 34%～44%。采用该工艺所得棕榈仁硬脂的熔点和固体脂肪含量与天然可可脂相当,氢化后产品在25～30℃的固体脂肪含量高于商业氢化棕榈仁硬脂代可可脂。     

1,3-二油酸-2-棕榈酸甘油三酯的合成

为了解决1,3-二油酸-2-棕榈酸甘油三酯(OPO)合成过程中不利于脂肪酶活性发挥的问题,采用两步法合成OPO,首先以棕榈硬脂和高油酸葵花籽油为原料通过化学酯交换反应得到相对棕榈硬脂熔点降低的油脂,再以化学酯交换油脂与油酸为原料在Lipozyme RM IM脂肪酶催化下进行酶法酸解反应得到OPO。通过单因素实验及响应面优化实验确定最优反应条件为棕榈硬脂与高油酸葵花籽油质量比2∶1、化学酯交换油脂与油酸质量比1∶1.45、酶添加量4%、反应温度50.40℃、反应时间5.29 h,该条件下OPO含量为27.26%,sn-2位棕榈酸占总棕榈酸含量为67.36%。以棕榈硬脂为原料合成OPO的新工艺一方面提升了高油酸植物油的使用价值,另一方面酶法酸解反应的温度适中,更有利于脂肪酶活性发挥。     

巴沙硬脂与6种油脂相容性的研究

利用固体脂肪含量等温曲线(SFC-T)和固体脂肪含量偏差曲线(ΔSFC-T),研究了几种常见的起酥油及人造奶油基料油——巴沙鱼油(BO)、棕榈仁油(PKO)、棕榈油中间分提物(PMF)、猪油(LO)、牛油及棕榈硬脂(PS)与巴沙硬脂之间的二元相容性。结果表明:熔点为53.1℃的棕榈硬脂及熔点为46.8℃的牛油与巴沙硬脂的相容性最好;其他油脂与巴沙硬脂混合时相容性较好的含量范围为棕榈仁油含量10%,棕榈油中间分提物含量10%~40%,猪油含量10%~20%及50%,巴沙鱼油含量10%~20%及50%。     

棉籽油硬脂和全氢化棉籽油硬脂的组成、热性质和微观结构分析

为扩大棉籽油用途，提高其附加值，采用气相色谱、高效液相色谱、低场脉冲核磁共振分析仪、差示扫描量热仪、X-射线衍射仪和偏光显微镜分析了棉籽油改性后的产物棉籽油硬脂(COS)和全氢化棉籽油硬脂(FHCOS)的脂肪酸组成、甘三酯组成、SFC含量、热性质和微观结构。结果表明：COS主要由不饱和脂肪酸和非三饱和的甘三酯组成，FHCOS几乎全部由饱和脂肪酸和三饱和甘三酯组成；随温度升高，COS的SFC不断降低，FHCOS的SFC在温度高于35℃时开始降低，相同温度下FHCOS的固体脂肪含量(SFC)均高于COS的，COS在结晶和熔化过程中均有2个峰，FHCOS有1个峰，FHCOS的熔化和结晶温度均高于COS的；COS在15℃时无明确的晶型及稳定的结构，FHCOS为二倍链长堆积的β′晶型，结晶体为针状或棒状，结晶聚集体为类似玫瑰花状。因此，以COS和FHCOS代替棕榈油作为生产起酥油、人造奶油、黄油等的基料油具有一定的开发和应用前景。     

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.     

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%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press