响应面优化脱酚棉籽粕制备棉籽多肽研究

棉籽粕经脱棉酚处理后,不经过提取棉籽蛋白的中间步骤,直接利用碱性蛋白酶酶解制备棉籽多肽。在单因素实验的基础上,选取酶解温度、酶解pH、加酶量、酶解时间为影响因素,应用响应面法的Box-Behnken中心组合实验进行设计,以棉籽多肽产率为响应值,对制备条件进一步优化。结果表明,采用响应面法得到的最佳制备工艺条件为:酶解温度56.4℃,酶解pH 9.7,加酶量8.4%,酶解时间4.1 h,底物浓度3%,此时的棉籽多肽产率为49.60%。     

两步酶法提取玉米胚芽蛋白的工艺研究

为确定更为温和、高效的玉米胚芽蛋白提取工艺,本实验采用纤维素酶和碱性蛋白酶对玉米胚芽进行两步酶法处理。通过单因素考察和正交实验设计对提取工艺参数进行优化。结果表明,纤维素酶酶解的最佳工艺为:pH4.5、酶解时间2.5h、加酶量0.3%(W/V);碱性蛋白酶酶解的最佳工艺为:pH9.0、酶解时间3h、加酶量4%(V/V)。在此条件下,玉米胚芽蛋白的提取率可达到83.7%±1.2%。     

小龙虾虾壳蛋白酶解条件的研究

文章主要介绍了以单酶、双酶协同分步酶解虾壳、虾头,以脱蛋白率(PR,%)为试验的衡量指标,对pH值、酶解温度、酶解时间、酶加量等试验条件进行考察。结果表明:胃蛋白酶的最优水解条件为pH值3.0,温度40℃,酶加量0.2%,水解时间4h,酶解液中蛋白质含量为4.243mg/mL,脱蛋白率最高达53.9%;碱性蛋白酶的最优水解条件为pH值7.5,温度55℃,酶加量0.3%,水解时间4h,酶解液中蛋白质含量为4.855mg/mL,脱蛋白率最高达61.9%;双酶协同分步酶解最优条件为碱性蛋白酶酶解3h(pH 7.5、温度40℃、酶加量0.3%),胃蛋白酶酶解1h(pH 3.0、温度40℃、酶加量0.2%),脱蛋白率为86.1%,酶解液中蛋白质含量为6.715mg/mL。     

微波辅助酶解棉籽粕的条件优化及酶解产物功能性质研究

研究了微波辅助碱性蛋白酶和风味蛋白酶双酶酶解棉籽粕的工艺条件.通过单因素实验确定了碱性蛋白酶酶解的最佳工艺条件为:微波温度60℃,微波功率500 W,酶加量5％(以底物质量计),酶解时间15 min;风味蛋白酶酶解的最佳工艺条件为:微波温度60℃,微波功率600W,酶加量5％(以底物质量计),酶解时间15 min.参照单因素优化条件,对棉籽粕进行连续酶解,酶解液多肽含量为13.32 mg/mL.棉籽粕经过微波连续双酶酶解后,吸油性、起泡性、乳化性等功能性质得到改善.     

联合酶法提取豆渣蛋白肽和可溶性膳食纤维

豆渣是大豆加工的主要副产物之一,含有丰富的蛋白质和膳食纤维。为促进豆渣高值化利用,采用联合酶法从豆渣中提取蛋白肽和可溶性膳食纤维（SDF）。首先用碱性蛋白酶酶解豆渣蛋白,以蛋白肽得率为指标,通过单因素试验优化了提取豆渣蛋白肽的工艺条件,再将脱蛋白豆渣用纤维素酶酶解制备SDF,以SDF提取率为指标,通过单因素试验优化提取SDF的工艺条件。结果表明：碱性蛋白酶酶解提取蛋白肽最佳工艺条件为料液比1∶ 35、酶与底物比2%、酶解时间5 h、酶解温度50 ℃、pH 95,在此条件下豆渣蛋白肽得率为66.81%;纤维素酶酶解提取SDF最佳工艺条件为料液比1∶ 30、酶与底物比3%、酶解温度50 ℃、酶解时间2 h、pH 4.0,在此条件下SDF提取率为1554%。利用碱性蛋白酶和纤维素酶依次酶解后,豆渣总利用率达到了89.81%,这为豆渣综合开发利用提供了一种新途径。     

酶法辅助提取、纯化米糠蛋白工艺优化

旨在为米糠副产品的精深加工利用提供指导,利用碱性蛋白酶辅助碱溶酸沉法提取米糠蛋白,并进一步以纤维素酶纯化米糠蛋白,在单因素实验的基础上通过正交实验优化提取、纯化工艺条件。结果表明：米糠蛋白提取的最佳工艺条件为酶解pH 10.5、酶解温度50℃、料液比1∶10、酶解时间120 min、加酶量2.5%,在此条件下米糠蛋白提取率为75.2%;米糠蛋白纯化的最佳工艺条件为酶解温度50℃、酶解pH 5.0、酶解时间60 min、加酶量4%、料液比1∶10,在此条件下米糠蛋白纯度为81.6%,提取率为72.6%。采用此方法可以得到提取率和纯度均较高的米糠蛋白。     

生物酶法制备香菇提取物的工艺研究

以香菇粉为对象,研究生物酶法制备香菇提取物的最佳工艺条件。主要采用纤维素酶、果胶酶、复合蛋白酶(蛋白酶H+风味蛋白酶)进行酶解,研究酶解温度、pH、加酶量、酶解时间分别对酶解过程的影响,以还原糖和氨基态氮为指标分析以上三种酶的最佳酶解条件。最后通过响应面法对多酶酶解体系进行初步研究,优化多酶酶解工艺。结果表明:多酶酶解香菇的最佳工艺条件:温度50℃,pH 7,酶解时纤维素酶添加量为0.6%,果胶酶添加量为0.3%,蛋白酶H加酶量0.4%,风味蛋白酶加酶量0.2%,酶解时间2.5h。     

双酶法水解双孢蘑菇蛋白的工艺研究

实验研究了纤维素酶和中性蛋白酶共同水解双孢蘑菇蛋白的水解工艺,以α-氨基氮含量为指标,确定了纤维素酶和中性蛋白酶的最佳水解条件为:先加纤维素酶,料液比1∶20,加酶量250 U/g,初始pH值6.0,酶解温度55℃,酶解时间120 min;后加中性蛋白酶,加酶量1500U/g,初始pH值6.5,酶解温度45℃,酶解时间150 min.经双酶水解后,α-氨基氮含量可达36.96mg/g.     

Alcalase 2.4L碱性内切酶和Flavourzyme风味酶酶解大豆分离蛋白及脱苦工艺优化

以大豆分离蛋白为原料,选用Alcalase 2.4L碱性内切酶和Flavourzyme风味蛋白酶对大豆分离蛋白进行酶法水解及脱苦工艺研究。以水解度和苦味分值为考察值,对酶解工艺进行优化,确定最佳条件。结果表明:Alcalase2.4L碱性内切酶最佳酶解条件为加酶量14 000 U/g、酶解温度60℃、酶解pH8.5、底物质量分数5%,酶解时间2h,最终水解度为45.34%,此时水解液苦味值为4。Flavourzyme风味蛋白酶对水解液进行二次水解的最优酶解条件为加酶量300 U/g、酶解温度55℃、酶解pH 7.0、酶解时间3 h,此条件下大豆分离蛋白水解液苦味值最低为1.2。Alcalase2.4L碱性内切酶和Flavourzyme风味蛋白酶水解大豆分离蛋白使水解度得到较大提高的同时也解决了水解液的苦味问题。     

复合酶水酶法提取大豆蛋白的工艺优化

采用复合酶水酶法提取大豆蛋白。水解酶选用碱性蛋白酶,复合酶采用纤维酶、半纤维酶、果胶酶。得出最优复合酶水酶法提取大豆蛋白工艺条件为料水比1:6(g/mL)、纤维素酶添加量0.64%、半纤维素酶添加量0.56%、酶解pH5、酶解温度37℃条件下水解0.75h后,再利用Alcalase碱性内切蛋白酶,加酶量1.85%、酶解温度50℃、酶解pH9.26、水解3.6h。经过验证实验可知,在最优酶解工艺条件下总蛋白提取率可达到极大值即85.78%。经过复合酶酶解预处理比传统的湿热预处理的总蛋白提取率提高了近10%,其原因经分析是经过复合酶酶解处理的豆粉其细胞结构充分破坏,使得酶的作用位点暴露更有利于蛋白酶的作用,具体的机理分析有待进一步研究。     

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