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.     

文蛤肉复合酶分步酶解工艺的研究

本实验探讨了中性蛋白酶和胰蛋白酶的复合酶与风味蛋白酶分步酶解文蛤肉的技术。 通过q检验法确定中性蛋白酶和胰蛋白酶最佳的复合比例,再通过正交试验探讨复合酶与风味蛋白酶二段酶解的最佳工艺参数,并以水解度、水解得率及风味评分值为指标对分步酶解工艺的最佳条件进行比较验证。结果表明,胰蛋白酶与中性蛋白酶的最佳复合比例为3:1,风味蛋白酶二段酶解的最优工艺参数为水解温度55℃、水解时间5.0h、加酶量1000 U/g(原料)、pH值(5.00±0.05),所得文蛤肉水解液中水解度、水解得率及风味评分值分别为55.97%、87.14%及230.98。     

文蛤肉的水解及文蛤调味酱的制备

试验了用双酶法水解新鲜文蛤肉。水解条件:pH6.5、温度50℃、底物浓度50%,加酶量为胰酶50U/g、中性蛋白酶50U/g,酶解时间4h。试验结果表明:采用胰酶、中性蛋白酶可使文蛤肉完全水解。在此基础上,制备了文蛤调味酱,得到了较好的结果。     

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。     

蛋白酶复合水解文蛤肉制备海鲜香料的工艺

以感官评分为指标,比较了不同种类蛋白酶和用酶量对文蛤肉水解液风味的影响,并采用正交实验优化了文蛤肉二段法复合酶解工艺条件:复合蛋白酶75 U/g,中性蛋白酶75 U/g,在45℃、自然pH下水解3 h;然后加入风味蛋白酶50 U/g,在50℃、自然pH下水解1 h。最终获得的水解液色泽为棕黄色,具有咸鲜滋味和明显蛤类特征香气,感官评分为5.5分,味精当量EUC高达53.25 g/L,氨基氮含量为4.16 g/L,水解度为35.3%,水解得率为36.4%,多肽含量为21.8 g/L。     

文蛤肉复合酶酶解技术研究

为开发高品质的文蛤肉蛋白水解液,采用单因素试验方法确定胰蛋白酶和精制中性蛋白酶的复合比例.采用二次正交旋转组合试验设计,探讨复合酶酶解文蛤肉的技术条件.结果表明,胰蛋白酶与精制中性蛋白酶的复合酶组合比例为3:1的酶解效果较好,复合酶酶解文蛤肉的最优生产工艺参数为加酶总量4 500U/g原料,酶解温度50℃,酶解时间3印min,pH(7.50±0.05),液固比3:1.在此条件下得到的酶解液的总氨基氮含量达296.24mg/100mL,酶解得率85.14%,风味评分值为209.51.建立了文蛤肉酶解液中总氨基氮含量Y1、酶解得率Y2、风味评分值Y3与加酶量X1、酶解温度X2、酶解时间X3的数学回归模型,置信度99%.     

红曲霉菌体蛋白复合酶解的研究

为了更好地综合利用红曲霉菌体滤渣,研究了红曲霉菌体的酶解条件.采用中性蛋白酶和碱性蛋白酶对红曲霉菌体进行复合酶解,通过试验,确定了适宜的复合酶解条件:中性蛋白酶酶量为5.0× 104U/g(菌体),碱性蛋白酶酶量为7.0×104U/g(菌体),酶解温度为50℃,pH值为7.5,底物浓度为40g/L,酶解时间为18h.在此最佳条件下,复合酶解的水解度达到10.60％,明显高于单一蛋白酶的水解度.     

酶解水牛奶制备抗凝血肽的工艺研究

目的:本文以新鲜水牛奶为原料,研究木瓜蛋白酶、中性蛋白酶及碱性蛋白酶复合酶解、混合酶解水牛奶的作用,比较不同水解方式的作用效果;并采用凝血酶滴定改进法测定水解液抗凝血活性。方法:分别进行三种蛋白酶单因素水解实验,确定各种酶的最适水解条件;在此基础上进行复合酶解与混合酶解实验,测定水解度和抗凝血活性。结果:木瓜蛋白酶的最适水解条件为:水解温度60℃、水解时间2.0 h、p H5.0、料水比1∶2(v/v)、酶用量6000 U/(m L底物);中性蛋白酶的最适条件为:水解温度40℃、水解时间3.0 h、料水比1∶2(v/v)、p H6.0、酶用量6000 U/(m L底物);碱性蛋白酶的最适条件为:水解温度50℃、水解时间4.0 h、料水比1∶2(v/v)、p H8.0、酶用量6000 U/(m L底物)。复合酶解法制备的水解液其抗凝血活性均高于混合酶解,最高抗凝血活性为52.0 ATU/m L。结论:本实验条件下,加酶组合为"中性蛋白酶-木瓜蛋白酶-碱性蛋白酶"的复合酶解制备的水解液具有最高的抗凝血活性,即52.0 ATU/m L。     

酶解虾壳蛋白制备ACE 抑制剂的工艺优化

以虾壳粉为原料,以水解度和ACE抑制率为指标,利用中性蛋白酶、碱性蛋白酶、菠萝蛋白酶和木瓜蛋白酶进行酶解,其中中性蛋白酶和碱性蛋白酶有较高的ACE抑制活性,因此对碱性蛋白酶和中性蛋白酶的工艺条件进一步优化。结果表明：碱性蛋白酶酶解工艺优化条件为：温度60℃、pH9.5、底物质量浓度2.5g/100mL、加酶量4000U/g、酶解时间2.5h,在此条件下ACE抑制率最高,为67.70%,水解度为69.79%;中性蛋白酶酶解工艺优化条件为：温度50℃、pH7.0、底物质量浓度2.5g/100mL、加酶量2000U/g、酶解时间2h,在此条件下ACE抑制率最高,为84.04%,水解度为26.76%。提示中性蛋白酶酶解能够产生更多的ACE抑制肽,是酶解虾壳蛋白制备ACE抑制肽的较优酶。     

双酶复合水解蜂蛹蛋白工艺研究

研究了脱脂蜂蛹蛋白的酶法水解工艺。以水解度和多肽得率为指标,从中性蛋白酶、碱性蛋白酶、木瓜蛋白酶、菠萝蛋白酶、风味酶中选出中性蛋白酶和碱性蛋白酶进行双酶复合水解。采用单因素与响应面优化设计,得出最佳酶解工艺条件为:复合酶比例1︰1(g/g)、加酶量4.67%、p H 8.27、料液比1︰12(g/m L)、酶解温度48.44℃、酶解时间4 h。此优化试验条件下,蜂蛹蛋白理论水解度46.05%,实际水解度为45.89%。此工艺可推广应用于蜂蛹蛋白多肽产业化生产的备选工艺。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press