响应面法优化波纹巴非蛤肌肉蛋白酶解工艺条件

波纹巴非蛤广泛分布于我国沿海地区,是一种高蛋白低脂肪的海洋蛋白资源。本研究以水解度、蛋白质回收率和感官评价为指标,选取动物水解蛋白酶、中性蛋白酶、风味蛋白酶、木瓜蛋白酶,采用单酶酶解和复合酶酶解波纹巴非蛤肌肉蛋白,综合指标筛选出最佳酶种类及酶解方法。并且以时间,液料比,加酶量为单因素,采用响应面优化酶解条件,确定最佳酶解工艺。研究结果表明:动物蛋白酶和风味蛋白酶按1∶1比例同时添加,酶解3 h后,酶解产物的水解度和蛋白质回收率分别达到22.29%±1.02%和79.95%±0.51%,感官评价总分为15.6,与其他酶解方式相比较好。通过单因素以及响应面优化,得到最佳酶解条件:加酶量1700 U/g,酶解时间3.5 h,液料比为3.4∶1。在此条件下,水解度为30.04%±0.64%,蛋白质回收率为81.46%±0.70%,与预测值水解度30.54%±0.137%和蛋白质回收率82.62%±0.092%无显著性差异(p0.05)。感官评价综合得分为15.8,风味较好,研究结果为波纹巴非蛤肌肉蛋白的精深加工利用提供参考。     

复合酶水解巴非蛤肉工艺研究

以巴非蛤肉为原料,选择木瓜蛋白酶、菠萝蛋白酶和中性蛋白酶分步水解制备水解液.通过时水解条件的研究,确定木瓜蛋白酶最适酶解条件为:酶用量6000U/g原料、料水比1:8(w/v)、50℃、pH6.5下酶解4h,水解度为35.84%.分步酶解的工艺条件为:在料水比1:8(w/v)、pH6.5、温度50℃条件下,用木瓜蛋白酶先水解4h,菠萝蛋白酶、中性蛋白酶再依次水解4h,水解度达到48.35%.复合酶水解液的氨基酸分析结果表明,游离氨基酸含量丰富,约为866.4mg/100mL(色氨酸未计),其中必需氨基酸占32.6%,尤其是谷氨酸、天门冬氨酸、甘氨酸等呈味氨基酸含量丰富.结果为巴非蛤肉复合水解液作为疗效营养剂或高级调味料提供了依据.     

酶法从芝麻中提取短肽

以黑芝麻为原料,用乙酸乙酯、异丙醇、石油醚3 种溶剂脱脂,再用碱提酸沉法提取出芝麻蛋白;利用木瓜蛋白酶、菠萝蛋白酶和碱性蛋白酶对其进行水解制备短肽,以水解度为考察指标优选出最佳单酶,通过正交试验对工艺条件进行优化并确定最佳水解条件。结果表明：乙酸乙酯脱脂效果最好,其脱脂率达90.22%;碱性蛋白酶为最佳单酶;在底物质量浓度1.0g/100mL、温度40.0℃、pH9.0、酶与底物质量比(E/S)3.0%、酶解时间4.0h 时水解度为24.10%,总氮回收率为78.28%,所制得短肽的平均肽链长度为2.93。     

柔性固定化木瓜蛋白酶的制备及在酶解波纹巴非蛤中的应用

在壳聚糖膜的表面接上分子链较长的双醛淀粉作为柔性固定化酶的载体,将木瓜蛋白酶固定在该载体上制成柔性固定化木瓜蛋白酶,并应用于酶解波纹巴非蛤制备小分子肽。通过考察温度、pH 值、加酶量和固定化时间等条件对柔性固定化木瓜蛋白酶的酶活、酶活回收率的影响,确定最优固定化条件。结果表明：双醛淀粉用量0.8mg/g 壳聚糖、柔性固定化酶温度25℃、柔性固定化酶时间20h、加酶量40mg/g 壳聚糖、pH8.0 条件下所得的固定化酶酶活最高,酶活回收率63.35%。将该柔性固定化酶在酶解温度40℃、pH7.0、加酶量1.0%、酶解时间4h条件下制备波纹巴非蛤小分子肽,产率为3.4055%。     

响应面法优化草鱼皮中有效抗氧化物质提取工艺

以草鱼皮为原料,采用六种蛋白酶酶解,以DPPH自由基清除率和水解度为指标,筛选两种较优的酶,再通过响应面分别优化两种酶制备抗氧化酶解液的工艺条件,并在此基础上进行双酶酶解实验,确定酶解草鱼皮的最优工艺。结果表明:碱性蛋白酶酶解草鱼皮的最适条件为加酶量6.3%、料水比1∶40.6、温度51.3℃、时间115.1 min,此时清除率最高为54.98%。木瓜蛋白酶最适条件为加酶量4.6%、料水比1∶41.2、温度50.5℃、时间133.0 min,清除率最高为41.06%。采用分步酶解(先碱性蛋白酶后木瓜蛋白酶)得到的酶解液DPPH自由基清除能力最高为92.07%,明显优于单酶水解和混合酶解的效果。     

牡丹籽蛋白酶解的工艺条件研究

以牡丹籽为原料制备植物源生物活性肽,本实验分别以水解度和蛋白含量为响应值,通过响应面实验,研究最佳酶解工艺,牡丹籽酶解液的水解度最优值固定在18.16%,其最优条件为:料水比1:5.4;加酶量7.9%;酶解时间5h;蛋白含量最优值固定在27.71mg/mL,其最优条件为:料水比1:7.7;加酶量5.3%;酶解时间3.2h;而后选用以水解度为指标的最佳酶解条件制备酶解液,使用高效液相色谱测定牡丹籽植物源生物活性肽的平均分子量为1210.83,占酶解产物的99.03%.     

环文蛤肉复合酶的水解工艺初探

以环文蛤为原料,采用酶水解的方法制备环文蛤肉水解液。先选用中性蛋白酶、碱性蛋白酶、木瓜蛋白酶和菠萝蛋白酶,分别对环文蛤肉进行单酶水解实验;并用复合酶解新技术对环文蛤肉进行水解研究。实验结果表明:3种酶复合水解的最佳工艺为:在料水比1:8(m/v)、pH7.0、50℃条件下,用中性蛋白酶6000U/g原料先水解4h,再依次使用碱性蛋白酶4000U/g、菠萝蛋白酶12500U/g连续水解4h后水解度达到43.27%。复合酶解液中游离氨基酸含量丰富,约为117.89μg/mL,其中必需氨基酸占51.39%。环文蛤肉经复合蛋白酶水解,适当调配可制作营养丰富、海鲜风味浓郁、具有一定保健功能的口服液。     

响应面法优化双酶水解黄鳍金枪鱼胰脏的工艺研究

本试验以水解度为指标,研究了酶解时间、酶活比、料液比、加酶量、pH和酶解温度6种因素对酶解反应的影响。在此基础上设计了3因素(酶解时间、pH和酶解温度)3水平的响应面试验,对木瓜蛋白酶与碱性蛋白酶双酶组合水解黄鳍金枪鱼胰脏制备生物活性肽的工艺进行优化,为获得高活性蛋白多肽及有效利用金枪鱼胰脏提供科学依据。结果表明,木瓜蛋白酶与碱性蛋白酶双酶水解黄鳍金枪鱼胰脏的最佳酶解条件为:酶活比1:1、料液比为1:10、加酶量30mg/g、pH7.55、酶解时间3.39h、酶解温度55.73℃。利用优化双酶水解条件制得的低分子多肽的水解度高达60.22%。     

山羊乳酪蛋白酶解工艺及抗氧化性研究

为了制备山羊乳酪蛋白活性肽,选用中性蛋白酶、胰蛋白酶、木瓜蛋白酶和碱性蛋白酶,采用对比和正交试验方法,研究了山羊乳酪蛋白单酶和复合酶的酶解工艺,测定了山羊乳酪蛋白的总肽键摩尔数,优选出了山羊乳酪蛋白的酶解工艺参数。结果表明：山羊乳酪蛋白的总肽键摩尔数为8.5379 mmol/g。单酶中胰蛋白酶和中性蛋白酶对山羊乳酪蛋白的水解度较大,木瓜蛋白酶较小。胰蛋白酶对山羊乳酪蛋白适宜的酶解工艺：加酶量2500 U/g,pH 7.5,50 ℃下酶解2 h。中性蛋白酶和胰蛋白酶复合以及中性蛋白酶、胰蛋白酶和木瓜蛋白酶三种酶复合的水解度较大,其水解度、平均肽链长度和平均相对分子量分别为17.34%、21.16%,5.77、4.73和692、567 u。     

文蛤的营养成分分析及其用于海味香精的酶解液制备

以文蛤肉为原料,测定其脂肪酸组成和无机离子含量,利用木瓜蛋白酶、枯草杆菌中性蛋白酶、复合风味蛋白酶对文蛤肉蛋白质进行水解,通过正交实验确定最适酶解条件。结果表明,文蛤中含有丰富的饱和脂肪酸和不饱和脂肪酸,EPA和DHA含量分别高达6.904%和7.244%,无机离子中呈咸味的Cl-含量最高,达601mg/100g。用于制取海味香精的文蛤肉酶解最适条件为:料水比1∶2,温度50℃,pH7.0左右(±0.1),先加入0.5%木瓜酶和0.3%中性酶水解1h,再加入0.4%风味酶继续水解3h,该条件下水解度为35.8%,总氮回收率为51.2%,感官评分为6.0分。     

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