分步酶解制备鲢鱼抗氧化肽的工艺研究

用分步酶解法制备鲢鱼抗氧化肽,首先从碱性蛋白酶、中性蛋白酶、胰蛋白酶、风味蛋白酶中筛选出碱性蛋白酶作为第一步酶解用酶,以水解度作评价指标,并得到酶解工艺条件:底物浓度15%,pH9.0,温度50℃,加酶量为24AU/kg。再从剩下的三种酶中筛选出胰蛋白酶与碱性蛋白酶复配,作为第二步酶解用酶,用响应面法进一步优化酶解工艺,考虑到成本和工艺的要求,最终确定的酶解工艺为:碱性蛋白酶水解时间为59.12min,胰蛋白酶水解时间为82.24min,两种酶的添加比例为1:1.48,即碱性蛋白酶添加量为24AU/kg,胰蛋白酶的添加量为35.5AU/kg。最终得到的鲢鱼抗氧化肽可溶性氮70.84%,多肽69.38%,水分4.21%,灰分25.67%;多肽浓度为2mg/mL时对DPPH自由基清除率为19.33%。      

鸡蛋壳膜多肽酶解工艺及抗氧化活性研究

试验以鸡蛋壳膜为原料,通过酶解法制备小分子肽,并对其生物活性进行研究。以水解度为评价指标,通过单因素试验确定蛋白酶种类、酶解时间、料液比以及酶添加量等因素对壳膜多肽水解度的影响,并通过响应面设计（Box-Behnken design,BBD）对酶解条件进行三因素三水平优化;通过高效凝胶过滤色谱测定酶解后壳膜多肽分子量的分布情况,并测定壳膜多肽对DPPH·、ABTS+·、·OH、O2-·的清除能力。结果表明,最佳酶解工艺条件为碱性蛋白酶（AP-200a）,酶添加量2.4%,料液比1∶9.5（g/mL）,酶解时间5 h;在此条件下,壳膜多肽水解度为27.15%,水解后相对分子质量小于1 000 Da的小分子肽所占比例为90.9%;且壳膜多肽对DPPH·、ABTS+·的清除率分别为（93.03±0.51）%、（94.53±0.92）%,与 VC的效果相当;但对·OH 和 O2-·的清除率分别为（43.33±1.10）%和（53.40±0.70）%。因此,通过该法酶解得到的壳膜多肽中小分子肽占比较高,易被人体消化吸收,且具有一定抗氧化活性。     

酶法水解卵黄蛋白制备多肽的工艺优化

利用酶法制备卵黄蛋白多肽。比较复合风味蛋白酶、中性蛋白酶、碱性蛋白酶、复合蛋白酶水解卵黄蛋白的效果,确定碱性蛋白酶与复合风味蛋白酶为复合酶解的工艺用酶。采用响应面分析法,以水解度、多肽含量为响应值,研究加酶量、酶用量比、复合酶解时间比、pH值对制备多肽工艺的影响。结果表明：酶法水解卵黄蛋白制备多肽的最佳工艺条件为：卵黄蛋白质量浓度10g/100mL、温度55℃、pH7.2,按0.8g/100mL添加碱性蛋白酶水解2h后,再按0.4g/100mL添加复合风味蛋白酶水解2h,在该条件下水解度和多肽含量分别为(13.31±0.5)%和(1.85±0.5)mg/mL。     

核桃多肽的制备及其体外抗氧化性研究

以核桃蛋白为原料,以水解度为指标,通过单因素和正交试验优化了碱性蛋白酶酶解核桃蛋白制备抗氧化肽的工艺参数。得到碱性蛋白酶最佳酶解条件为酶添加量5%,底物浓度3%,酶解温度55℃,酶解p H为9.0,酶解时间6 h;在各酶最佳条件下获得的核桃多肽具有一定的抗氧化性。     

羊骨多肽酶法制备工艺优化及抗氧化活性研究

以羊骨粉为原料,用碱性蛋白酶进行酶解制备具有抗氧化活性的酶解多肽液。以水解度为指标,优化了羊骨多肽酶法制备工艺条件,并对酶解液的抗氧化能力进行了测定。结果表明,碱性蛋白酶制备羊骨多肽的最佳制备工艺条件为酶解时间5 h,酶解温度45 ℃,加酶量8 200 U/g,酶解pH值10,该条件下羊骨粉的水解度为(28.36±0.02)%。羊骨粉酶解液与对照组(未被碱性蛋白酶酶解的羊骨粉溶液)的抗氧化能力均随着溶液浓度的增加而上升,当酶解液浓度达到2.5 mg/mL时对DPPH自由基、羟自由基、超氧阴离子自由基清除率和还原力均达最大值,分别为(65.42±0.11)%,(82.30±0.27)%,(79.83±0.22)%,0.484±0.007,显著高于对照组(P＜0.05)。说明碱性蛋白酶水解羊骨粉得到的酶解多肽液具有体外抗氧化活性。     

液压压榨澳洲坚果粕酶解制备多肽工艺优化

以液压压榨澳洲坚果粕为原料,分析了其常规营养成分含量与氨基酸组成。采用碱性蛋白酶与中性蛋白酶催化酶解澳洲坚果粕蛋白制备多肽。以水解度为指标,利用单因素试验与正交试验考察了各因素对澳洲坚果粕蛋白水解度的影响。结果表明：液压压榨澳洲坚果粕中含有32.25%的蛋白质,17 种氨基酸,含量为25.05%。碱性蛋白酶各因素对澳洲坚果粕蛋白水解度影响的主次顺序为：酶解时间＞酶解温度＞加酶量＞酶解pH值＞底物质量浓度,最佳工艺条件为：酶解温度60 ℃、酶解时间3.5 h、底物质量浓度110 g/L、酶解pH 8.0、加酶量2 400 U/g,在此条件下水解度达到了22.83%。中性蛋白酶各因素影响水解度的主次顺序为：加酶量＞酶解时间＞底物质量浓度＞酶解温度＞酶解pH值,最佳工艺条件为酶解温度55 ℃、酶解时间3.5 h、底物质量浓度100 g/L、酶解pH 7.0、加酶量3 200 U/g,水解度达到了22.78%。碱性蛋白酶与中性蛋白酶各因素对澳洲坚果粕蛋白水解度的影响均达到了极显著水平（P＜0.01）。在最佳工艺条件下,碱性蛋白酶酶解液压压榨澳洲坚果粕制备多肽的效果优于中性蛋白酶。     

葡萄籽多肽制备及其自由基清除能力的研究

用复合酶(碱性蛋白酶、木瓜蛋白酶)水解方法制备葡萄籽多肽,通过单因素试验考察酶添加量、酶解时间、酶解温度和酶解p H值对脱脂葡萄籽蛋白水解度的影响。在基于单因素试验的条件下,选用三因素三水平试验确定复合酶分析3个因素对响应值的影响。结果表明最佳酶解工艺参数为:复合蛋白酶质量比例为7∶3,酶添加量为2%、酶解时间3 h、酶解温度50℃、pH 7.4,在该条件下脱脂葡萄籽蛋白的水解度达24.33%,葡萄籽蛋白复合蛋白酶酶解物在质量浓度为120μg/mL～600μg/mL的范围内,其对DPPH自由基的清除能力为19.25%～41.03%,且存在明显的量效关系,与VC、VE相比,葡萄籽多肽用量为0.15%时抗氧化效果较好。     

基于灰色关联分析法的大豆蛋白酶解工艺优化

为使灰色关联分析法在食品领域得到充分的应用,并为食品工业提供优质的大豆多肽资源。采用单因素试验考察不同酶解条件对大豆蛋白酶解的影响,并利用灰色关联分析法建立蛋白酶解过程模型。利用Alcalase碱性蛋白酶(4.4万U/g)对大豆低温豆粕进行酶解,制备大豆多肽。通过灰色关联分析法计算反应体系pH值、反应温度、反应时间、大豆脱脂豆粕添加量以及Alcalase碱性蛋白酶添加量的关联系数,得到各因素显著性大小为pH值温度底物浓度加酶量时间。经实验验证水解度与预测水解度基本一致,证明试验得出的结论可靠。其最佳工艺参数为:反应体系pH值9.0,反应温度55℃,反应时间3h,大豆脱脂豆粕添加量5%(m/V),Alcalase碱性蛋白酶的添加量1 500U/g,该条件下水解度为13.53%。     

酶解条件对核桃多肽抗氧化活性的影响

以核桃蛋白粉为原料制备核桃蛋白抗氧化活性肽,分别采用中性蛋白酶、碱性蛋白酶、木瓜蛋白酶对核桃蛋白进行酶解,测定了不同酶作用下的核桃多肽抗氧化活性,确定碱性蛋白酶是酶解核桃蛋白的最适蛋白酶。研究了酶解温度、酶解时间、酶解pH、底物浓度、酶添加量等酶解条件对酶解产物抗氧化活性的影响。结果表明:不同的酶解条件对酶解产物核桃多肽的抗氧化活性有显著影响,最佳酶解条件为:温度50℃,时间120 min,pH8,底物浓度3%,酶添加量3%,在此酶解条件下制得的核桃多肽对羟基自由基和超氧阴离子的清除率分别为53.8%和50.0%,还原能力为51.7%。     

紫苏粕酶解工艺优化及其多肽抗氧化稳定性

为更好地利用紫苏粕中的蛋白质资源,采用碱性蛋白酶酶解脱脂紫苏粕制备紫苏粕多肽,以水解度为指标,在单因素试验基础上,采用响应面法优化紫苏粕多肽制备工艺,并对最优条件下制备的紫苏粕多肽进行氨基酸组成和抗氧化稳定性分析。结果表明,最佳酶解工艺为酶解时间8 h、初始pH11.5、底物浓度7.5%、酶解温度60 ℃、加酶量7 000 U/g。在此条件下,酶解液水解度为（23.462±0.237）%。紫苏粕多肽由17 种氨基酸组成,其中精氨酸含量最高,达（286.635±0.357）mg/g。紫苏粕多肽在20～100 ℃、pH2～8 保持较强的抗氧化活性。添加适量NaCl 和葡萄糖有助于增强紫苏粕多肽抗氧化活性,添加2%以上柠檬酸则导致ABTS+自由基清除活性显著下降。综上,该工艺制备的紫苏粕多肽具有良好的抗氧化稳定性,具有进一步开发潜力。     

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