挤压膨化及添加粗酶对水相制取大豆油和蛋白质的影响

以全脂豆粉为研究对象,考察挤压膨化和添加粗酶对水相制油工艺中总油、总蛋白提取率及蛋白性质的影响。结果显示,全脂豆粉未经挤压膨化和无粗酶添加的水相提油工艺,总油和总蛋白得率较低,分别为60.31%和66.33%,采用挤压膨化豆粉而未添加粗酶水相制油工艺的总油提取率为65.12%,总蛋白提取率为55.1%;添加粗酶而豆粉未经挤压膨化的制油工艺总油和总蛋白提取率与无粗酶水相提取未膨化豆粉的总油和总蛋白得率相似;而挤压膨化联合粗酶添加却使水相制油工艺的总油、总蛋白提取率显著提升,分别达到94.25%和90.13%。由于酶水解造成蛋白在pH4.5附近溶解性增加,因此水相粗酶制油工艺采用等电点方式回收蛋白得率较低。相比于无酶添加的水相制油工艺,挤压膨化联合粗酶提油工艺所得蛋白的溶解性、持水性更好,而黏度、疏水性、吸油性、乳化性和乳化稳定性、起泡性和泡沫稳定性等性能均有所下降。     

真空挤压膨化预处理水酶法提取大豆蛋白工艺研究

以大豆为原料,对真空挤压膨化预处理水酶法提取大豆蛋白工艺进行研究。在单因素试验基础上,通过响应面分析法对真空挤压膨化预处理工艺进行优化,确定最优工艺条件为:真空度-0.057 MPa,物料含水率15%,套筒温度94℃,螺杆转速98 r/min,模孔孔径17 mm。在最优工艺条件下总蛋白提取率高达92.17%,比传统湿热预处理工艺提高了近14个百分点;同时,提油效果显著,总油提取率高达93.61%。     

发酵全脂大豆粉提取油和蛋白的研究

采用发酵工艺分别联合磨碎和挤压膨化前处理技术制取大豆油和蛋白,通过油和蛋白得率及其品质评估工艺的可行性。结果显示发酵全脂豆粉联合挤压膨化能够显著提高油和蛋白提取率,总油和总蛋白得率分别为95.1%和87.12%,与水酶法得率相近,显著高于磨碎前处理工艺。磨碎豆粉与膨化豆粉经发酵提取油的品质和脂肪酸组成相似,均优于溶剂浸提油;磨碎与膨化豆粉发酵所得分离蛋白(FE-SPI和FGSPI)分子质量主要分布在10 000 u以下,FE-SPI的功能性优于或接近于FG-SPI,二者的溶解性、持水性显著优于碱溶酸沉制取的分离蛋白(W-SPI),但疏水性、持油性、乳化性、发泡性能及黏度均低于W-SPI。研究证实发酵联合挤压膨化提取大豆油作为一项环境友好制油技术具有良好的应用前景。     

不同加工工艺对一种固体饮料品质的影响

通过热风干燥、真空干燥、真空冷冻干燥和挤压膨化4种工艺加工固体饮料,并测定其理化特性和活性成分。结果表明,真空干燥和真空冷冻干燥制得的固体饮料色泽较好,挤压膨化制得的固体饮料溶解性、吸湿性、黏度都高于其他几种工艺,但是热风工艺的全粉得率最高,真空冷冻干燥加工制得的固体饮料的活性成分（总黄酮和总生物碱）损失较少。综合看来,真空冷冻干燥加工制得的固体饮料品质最好,其次是使用真空干燥和挤压膨化方法的,热风干燥制得的固体饮料品质最差。     

挤压膨化对大豆油脱胶工艺的影响

讨论了挤压膨化对脱胶工艺的影响。对挤压膨化大豆毛油而言 ,水化脱胶效率达 97 9% ,比非挤压膨化毛油的脱胶效率 (92 2 % )要高得多。另外 ,磷酸、柠檬酸和乙酸酐对毛油中的非水化磷脂的脱除有明显作用 ,但同时会降低磷脂副产物的价值     

挤压膨化后微体化预处理水酶法提取大豆油脂工艺研究

在单因素实验的基础上,选取挤压温度、螺杆转速、物料含水量、模孔孔径和膨化后物料粉碎粒度5个因素为自变量,以总油提取率为响应值,进行响应面实验设计,确定了最佳提油率下的挤压-微体化参数。结果表明,挤压最佳条件为温度96℃、螺杆转速96r/min、物料含水率14.6%、模孔孔径15mm、膨化后物料粉碎粒度120目,此时提油率为94.34%±0.74%。并且采用红外光谱分析了大豆挤压膨化前后提取的大豆分离蛋白二级结构变化,进而讨论蛋白结构变化对水酶法提取油脂过程中油脂释放的影响,结果表明,挤压膨化后蛋白质二级结构中β-折叠含量降低,无规卷曲含量升高,蛋白质由有序向无序结构的转化,可以使得酶解过程中油脂释放量增加。     

猴头菇多糖挤压膨化预处理提取工艺优化

采用挤压膨化技术与植物化学物现代提取分离技术相结合,根据药食同源药味的作用特点,将猴头菇经双螺杆挤压机挤压膨化后采用水提醇沉法进行多糖提取,而后选择蒽酮硫酸法测定多糖含量。首先采用单因素试验考察螺杆转速、水分含量、挤压温度3个因素对猴头菇中多糖提取率的影响,筛选出最佳水平后,以多糖提取率为响应值,采用响应面分析法进一步优化,从而确定其多糖提取的最佳挤压膨化参数。最终优化结果为:螺杆转速400 r/min,水分含量16%,挤压温度120℃。在最优工艺验证试验下多糖得率可达3.63%,与预测值非常接近,说明响应面法建立的模型预测性良好,能够合理地优化挤压膨化预处理提取工艺。     

真空挤压膨化法制备阳离子淀粉工艺研究

以马铃薯淀粉为原料,采用真空挤压膨化法制备阳离子淀粉。在单因素试验基础上,通过响应面试验对真空挤压膨化法制备阳离子淀粉工艺进行优化,确定最优工艺条件为:物料含水率19.8%,真空度-0.102 MPa,套筒温度140.4℃,螺杆转速395 r/min。在最优的工艺条件下,取代度为0.172,反应效率为95.81%。     

水酶法制取大豆油的水解度对提油率影响机理研究

以挤压膨化预处理后的全脂大豆粉为原料,在单因素试验的研究基础上,以加酶量、酶解温度、酶解时间、料水比和酶解pH五个因素为自变量,以总油提取率与水解度为响应值,得到适宜的酶解条件为:加酶量1.8%、温度52℃、酶解时间3.75h、料水比1:6.5、pH9.4,经过验证与对比试验可知,在优化的酶解工艺条件下总油提取率可达到91.67%,对应的水解度为26.37%。对2个考察指标的降维分析图进行对比分析,探讨了水解状态与脂肪分子释放情况以及脂蛋白分解情况的关系,为水酶法生产大豆油提供理论基础。     

油料挤压膨化机的正确选用

目前 ,我国大多数油脂厂均采用浸出法制油。油脂的生产过程一般包括油料预处理、浸出、精炼等工序。其中 ,油料预处理在整个工艺中具有十分重要地位 ,对油脂的品质、提取率、生产效率等影响较大。传统的油料预处理方法由于对轧胚工艺要求高、浸出效率低逐渐被新的挤压膨化预处理技术所代替。早在 2 0世纪 60年代 ,美国、巴西已开始采用挤压膨化预处理工艺浸出制油 ,由于油料经挤压膨化后 ,容重增大 ,并呈微孔状 ,其渗透性被大大提高 ,浸出溶剂的通过料层速度也大大加快 ,由此 ,浸出器的生产能力被显著提高 ,而且大大降低了浸出溶剂回收能耗。所以 ,随着人们对油料挤压膨化技术在油脂生产中应用优势的认识 ,近年来挤压膨化技术被广泛地应用于油脂和饲料的生产 ,为此 ,本文就油料挤压膨化机合理选用及其正确使用等进行论述 ,为厂家正确应用油料挤压膨化机提供指导性意见 ,使油料膨化技术在生产中真正起到作用 ,达到增产、降耗、提高浸出效率之目的。     

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