草鱼蛋白酶解及脱腥脱苦工艺研究

研究以草鱼为原料,选用动物蛋白水解酶和风味蛋白酶混合同时酶解,然后选用活性碳为脱腥脱苦试剂,通过正交试验对酶解液脱腥脱苦工艺条件进行了探讨.结果表明:双酶的最佳酶解条件为蛋白酶(动物蛋白水解酶∶风味蛋白酶)用量比2 ∶ 1(W ∶ W),酶解温度55℃,pH值7.5,料液比1∶2,酶解时间6h,水解度达到33.64％,氨基氮含量为317.35mg/dL;活性碳最佳脱腥脱苦工艺条件:活性碳添加量0.6％(W ∶ V),时间1.5h,温度50℃.此条件下得到的水解液腥苦味能得到很好的去除,并且酶解液颜色较浅具有良好的风味.     

Alcalase 2.4L酶解核桃分离蛋白制备ACE抑制肽的工艺研究

以核桃分离蛋白(WPI)为原料,利用Alcalase 2.4L酶解制备高活性的ACE抑制肽.以水解度和ACE抑制率为指标,通过单因素和二次回归正交旋转组合试验,优化了Alcalase 2.4L酶解核桃分离蛋白制备ACE抑制肽的工艺.得到的最佳酶解工艺条件为pH 7.94,酶解温度60℃,底物质量浓度20g/L,酶与底物质量比3.69∶100,酶解3h后,酶解产物的水解度达到24.78％,ACE抑制率达到76.58％,且在此条件下获得的ACE抑制肽具有一定的抗体内消化酶特性.     

糯米粉酶解工艺优化及在低脂冰淇淋中的应用

以糯米粉为原料酶解为糯米糖浆,通过响应曲面优化实验,确定最佳酶解工艺条件为酶解时间29.26min、酶解温度75.31℃、酶用量0.71g/L,在此条件下DE值的预测值为7.08%,实测值平均值为7.14%。以该糯米糖浆为原料取代奶油制作冰淇淋,可获得脂肪含量为0.86%,蛋白质含量为2.93%的低脂冰淇淋。     

酶解蚕豆蛋白制备多肽酒及其抗氧化性研究

以蚕豆蛋白为原料,采用碱性蛋白酶酶解、酒精发酵制备蚕豆多肽酒,并对其抗氧化性进行了研究.结果表明:蚕豆蛋白酶解优化工艺为底物浓度32 g/L,水解温度43.2℃,酶用量9 821.12 U/g,pH 9.50,在此条件下酶解2h,蚕豆蛋白的水解度达到19.64％.以蚕豆酶解液为原料制备多肽酒的发酵工艺为加糖量20％,酵母接种量0.22％,发酵温度28℃,发酵时间6d,在此条件下制得的蚕豆多肽酒的酒精含量为9.6％,呈透明的棕黄色,口感醇正、鲜爽、具有发酵酒的醇香.本试验条件下制备的蚕豆多肽酒具有较强的抗氧化性.     

螺旋藻蛋白酶解工艺的优化及螺旋藻肽的制备

利用碱性蛋白酶37071对螺旋藻蛋白进行了酶解,探究了酶解pH、酶解时间以及热处理对酶解效率的影响,得到螺旋藻蛋白酶解的最佳工艺条件为:酶解pH 8,酶解时间24 h,热处理100℃。此时,螺旋藻蛋白回收率达到51.78%,水解度为13.16%。在此最优工艺条件下,制备得到了螺旋藻肽,并对该肽的蛋白含量、氨氮含量、氨基酸组成、总糖含量、分子量分布以及金属元素含量进行了测定。     

酶法提取杏仁油工艺的优化研究

对杏仁油提取中的酶解工艺进行了初步研究。采用五因素四水平正交设计对酶解条件进行了优化试验。结果表明：酶解工艺参数分别为温度37℃、PH值8．0、酶解时间1．5h、酶用量0．4％和水磨目数100目时，提曲率最高。再经无交互作用方差分析发现：玉因素影响程度大小依次为温度、酶用量、水磨目数、酶解时间。经酶法提取的各仁油具有良好的品质。     

米渣蛋白肽的新型酶解工艺及产品结构表征

米渣经过前处理去除糖类、脂质后得到米渣蛋白,再经酶解、脱色等处理后喷雾干燥得到米蛋白肽粉 以溶解性蛋白含量为指标,采用正交实验法对酶解工艺进行优化,得到最佳条件为:胰蛋白酶与复合蛋白酶配比为3∶2、酶解固液比1∶9、温度50 ℃、pH8.0、时间3.0h,蛋白肽产品溶解性蛋白、短肽含量分别从酶解前的4.35％、0.97％提高至23.49％、16.35％ 采用红外光谱、粒径分布和扫描电镜对产品米渣蛋白肤分子进行了表征,表明此工艺制得的蛋白肽纯度较高.     

湿热及酶解处理对糯米粉体外消化特性和血糖生成指数的影响

目的 研究酶解处理、湿热处理和湿热复合酶解处理对糯米粉体外消化特性和血糖生成指数(glycemic index, GI)的影响。方法 采用体外消化法测定了不同处理糯米粉的水解度和血糖生成指数值, 并通过X-射线衍射和激光共焦拉曼光谱实验测定了不同处理糯米的淀粉晶体结构。结果 3种处理的水解度和抗性淀粉(resistant starch, RS)相对含量增加, 慢消化淀粉(slowly digestible starch, SDS)相对含量降低; 其中湿热复合酶解处理条件下, RS相对含量最高, 为71.31%; 酶解处理条件下, RS相对含量最低, 为67.66%。酶解处理、湿热处理和湿热复合酶解处理的GI值分别为79.1、76.0和70.6。3种处理后糯米淀粉的晶体结构发生改变, 3种处理均使分子短程有序度与结晶度增加, 其中湿热复合酶解处理条件下, 结晶度最高, 为34.41%。 结论 湿热复合酶解处理后的糯米粉抗消化特性增强且GI值降低, 湿热复合酶解工艺可能通过影响糯米粉的体外消化率来降低GI值。     

碱性蛋白酶水解小麦面筋蛋白制取Gln肽的研究

采用单因素和正交实验研究碱性蛋白酶Alcalase酶解小麦蛋白获得高谷氨酰胺含量肽的优化工艺。使用氨基酸分析仪测定肽中有效谷氨酰胺含量。结果表明：碱性蛋白酶Alcalase水解小麦面筋蛋白的最适条件为pH 8.0，温度 70 ℃，酶浓度 E/S 4％，底物浓度 7％，反应时间 150 min。在此条件下，酶解产物中的有效谷氨酰胺含量为 17.65％，占酶解样品中Glx（Gln与Glu之和，含量22.83％）的 77.31％，三氯乙酸氮溶指数（TCA-NSI）为 77.86％，蛋白含量 76.03％，游离氨基酸含量 2.06％，说明酶解产物的有效Gln含量高，且肽含量高。     

酶解制备猪小肠粘膜蛋白粉工艺条件优化

为研究蛋白酶酶解制备猪肠粘膜蛋白粉工艺,以天然猪肠衣加工副产物肠粘膜为原料,以酶解产物中可溶性蛋白含量为指标,通过单因素实验和响应面实验,筛选适宜用于酶解猪小肠粘膜的蛋白酶并对其酶解工艺条件进行优化。结果表明,木瓜蛋白酶酶解猪肠粘膜制备蛋白粉可溶性蛋白含量达7.37%±0.06%,显著高于胰蛋白酶和胃蛋白酶酶解制备得到的肠粘膜蛋白粉可溶性蛋白含量,最佳酶解工艺条件为:水解时间6.5 h,酶添加量5400 U/g蛋白,液固比4 mL/g,在此条件下酶解产物中可溶性蛋白含量为15.81%±0.04%,这表明酶法制备肠粘膜蛋白粉工艺合理可行,为动物副产物的开发利用提供参考依据。     

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