挤压工艺参数对高水分组织化小麦蛋白产品特性的影响

研究含水量、螺杆转速、喂料速度、挤压温度等挤压工艺参数对高水分组织化小麦蛋白产品特性的影响。以小麦蛋白为主要原料,采用高扭矩双螺杆挤压装备开发高水分组织化小麦蛋白,并分析了产品色泽品质(L~*、a~*、b~*、ΔE)、质构特性(组织化度、硬度、黏着性、弹性、聚结性、咀嚼度)、感官评价。结果表明:随着含水量的升高,组织化蛋白产品色泽品质呈上升趋势,质构特性(组织化度先下降后升高)呈下降趋势;随着螺杆转速的升高,组织化蛋白产品色泽品质呈先升高后下降趋势,质构特性呈先下降后升高趋势;随着喂料速度的升高,组织化蛋白产品色泽品质、质构特性(组织化度先下降后略有升高)呈上升趋势;随着挤压温度的升高,组织化蛋白产品色泽品质、质构特性呈先升高后下降趋势。综合考虑组织化蛋白产品色泽品质、质构特性和感官评价,较适宜的挤压工艺为含水量49%,螺杆转速330 r/min,喂料速度10~11 kg/h,挤压温度170℃。     

挤压处理下组织化核桃蛋白品质变化

作为核桃制油副产物的核桃蛋白是一种优质植物蛋白,核桃蛋白高值化利用,对核桃产业可持续发展具有重要意义。该研究采用挤压法对核桃蛋白进行组织化,考察挤压工艺参数对组织化核桃蛋白色泽、质构特性和组织化度的影响。通过采用单因素法,研究了挤压温度、水分含量、螺杆转速、喂料速度和冷却温度5个挤压工艺参数对组织化核桃蛋白的影响。根据单因素试验结果,选择挤压温度、水分含量和喂料速度三个参数为响应面实验的试验因素,以组织化度为响应值,应用响应面分析法对挤压工艺参数进行优化,得到了最优挤压工艺参数为挤压温度141 ℃,水分含量52.7%,螺杆转速160 r/min,喂料速度26 g/min,冷却温度65 ℃,此时组织化度为1.209。该研究为核桃蛋白基素肉开发奠定了基础。     

高水分挤压组织化植物蛋白纤维结构形成机制研究进展

高水分挤压组织化技术是目前生产具有类似动物肉的纤维结构和口感的组织化植物蛋白的主要加工技术。旨在为未来新型植物性肉类类似物的加工和产品设计提供理论参考,从原辅料(植物蛋白、添加剂)、挤压系统参数(水添加量、挤压温度、螺杆转速和喂料速度)、冷却模头三个方面阐述对植物蛋白高水分挤压过程中纤维结构形成的影响机制。蛋白质分子间相互作用力是组织化植物蛋白纤维结构形成的关键,而不同的植物蛋白原料其组织化结构所依赖的蛋白质分子间作用力不同。添加剂可以改变蛋白质等分子内或分子间的作用方式和程度,从而直接影响组织化植物蛋白成品纤维结构的形成。挤压参数主要通过影响蛋白质结构来影响产品质构特性。冷却模头有利于各向异性纤维结构的形成。     

双螺杆挤压对大豆组织蛋白组织化度的影响研究

以大豆浓缩蛋白为原料,采用双螺杆挤压组织化技术,对大豆组织蛋白的组织化度进行了研究。结果表明：影响大豆组织蛋白组织化度的主要因素是温度,其次是螺杆转速与水分,喂料转速最小,最佳工艺是挤压温度180℃,水分38%,螺杆转速9Hz,喂料转速11Hz。     

操作参数对组织化大豆蛋白产品特性的影响

低温脱脂豆粕的组织化加工是提高豆粕利用率的有效途径.以低温脱脂豆粕为原料,应用DSE-25型双螺杆挤压实验室工作站,分析了物料含水率、机筒温度、喂料速度、螺杆转速等操作参数对组织化大豆蛋白质构特性和理化特性的影响.结果表明:随着物料含水率的增加,咀嚼性下降,组织化度(TI)提高,在较高的物料含水率(45%、50%)条件下,氮溶解指数(NSI)较低,水分保持能力(WHC)较高;随着机筒温度的升高,TI和NSI逐渐增加,WHC先下降后上升,咀嚼性在140℃有明显降低趋势;随着喂料速度的增加,咀嚼性、TI、WHC、NSI下降;随着螺杆转速的增加,WHC和TI逐渐下降,咀嚼性、NSI基本不变;从理化特性和质构特性两个角度考虑,适宜的操作参数应为物料含水率45%～50%,机筒温度为140～150℃,喂料速度在30 g/min以下,螺杆转速为90 r/min.     

响应面法优化低值水产蛋白组织化加工工艺

目的:以北太平洋鱿鱼加工的边角料为原料,使用双螺杆挤压机研究挤压技术在低值水产蛋白组织化加工中的应用.方法:选取物料湿度、机筒温度和螺杆转速3个因素,分析其对挤出物组织化度和咀嚼度的影响;采用三因子二次回归正交旋转组合设计,对低值水产蛋白组织化加工工艺进行优化.通过试验数据推导描述2个评价指标的二次回归模型,并对其变量进行响应面分析.结果:优化得到最佳挤压工艺条件为物料湿度40.65％、机筒温度140℃、螺杆转速25.75 Hz.挤出物组织化度与操作参数,挤出物咀嚼度与操作参数的回归拟合的相关系数R2分别为0.889和0.882.结论:拟合的统计模型可信度高,本研究结果对低值水产蛋白资源组织化技术的研究有很好的借鉴意义.     

热塑挤压蒸煮处理技术对大豆蛋白基本特性的影响

利用双轴挤压蒸煮处理技术对大豆蛋白进行处理,从质构特性、功能特性及营养特性等三方面对挤出物的组织化效果进行研究。以三个挤压操作参数供水率、螺杆转速和腔体温度为输入参数,挤出物的最大剪切力、复水率、持水率和蛋白质体外消化率为响应参数,探索挤压蒸煮系统操作参数对大豆蛋白质基本特性的影响规律,统计分析表明,三个挤压操作参数与响应参数之间存在显著的相关关系,所得拟合回归模型具有较高的可信度。挤压蒸煮处理操作参数对大豆蛋白的组织化效果有明显影响。     

水热参数组合对大豆蛋白-鱼糜共混高水分挤压过程及产品品质的影响

高水分挤压技术是制备具有类似动物肉纤维结构和质地的新型植物基肉制品的前沿热点技术。本实验以大豆分离蛋白（soy protein isolate,SPI）和金线鱼鱼糜为原料（80∶20,m/m）,探究水热参数组合（物料水分质量分数65%、70%、75%,挤压温度125、135、145 ℃）对高水分挤压过程中单位机械能耗（specific mechanical energy,SME）和模口压力的影响,以及对挤出物品质的调控作用。结果表明：在实验所用水热参数组合条件下,高水分挤压过程中,鱼糜凝胶以颗粒形式填充在混合凝胶中,并会影响带有取向性的凝胶结构形成。物料水分质量分数增加的同时提高挤压温度会导致高水分挤压过程中的SME从783.40 kJ/kg显著降低到410.96 kJ/kg（P＜0.05）,模口压力从7.79 MPa显著降低到1.60 MPa（P＜0.05）。水热参数组合作用显著影响SPI-鱼糜混合挤出物的品质,与挤压温度相比,物料水分质量分数影响效果更为显著,当物料水分质量分数为70%、挤压温度为145 ℃时,挤出物组织化程度达到最大（2.36）。多项式拟合结果表明,水热参数组合条件下,高水分挤压过程中的SME和模口压力与SPI-鱼糜混合挤出物硬度、咀嚼度、凝胶强度、持水性和剪切力具有非线性相关关系。本研究可为实现植物蛋白和动物蛋白优势互补、开发动植物蛋白结合的替代蛋白类新产品提供参考和借鉴。     

挤压工艺对保鲜方便米饭品质的影响

以双螺杆挤压机加工保鲜方便米饭,研究了进料糊化度、进料水分含量、进料粒度、螺杆转速对方便米饭品质的影响。通过分析感官评定与质构参数的相关性,确定以硬度和咀嚼性为指标评价挤压保鲜方便米饭的挤压工艺。采用单因素试验和正交试验,优化了挤压工艺条件:进料粒度0.425 mm,进料糊化度50%,进料水分质量分数25%,挤压机螺杆转速90 r/min。在此条件下制备的方便米饭硬度为113.56 g,咀嚼性为63.81。米饭颗粒饱满,色泽晶莹,咀嚼性适中,口感好。     

大豆蛋白高水分挤压组织化过程中工艺参数对系统压力和扭矩的影响

以食用脱脂低温豆粕为原料,用响应面分析法,研究了DSE-25型双螺杆挤压机在大豆蛋白高水分挤压组织化过程中工艺参数对系统压力和扭矩的影响。结果表明,机筒温度、物料水分含量、喂料速度和螺杆转速等操作参数对挤压机系统压力和扭矩均具有显著的影响。系统压力随着机筒温度和物料水分含量的升高而降低,随着喂料速度的增加而增加,螺杆转速对其影响较小;扭矩随物料水分含量的增加而降低,随着机筒温度和螺杆转速的升高均表现出先升后降的趋势,随喂料速度的增加则表现出先降后升的趋势。依据逐步回归分析法建立的双螺杆挤压机系统参数的统计模型,具有较高的预测精度,可用于挤压过程的控制和挤压结果的预测。     

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