不同酶水解鱼蛋白起泡性对比研究

以鱼蛋白粉为原料,采用碱性蛋白酶和木瓜蛋白酶分别水解鱼蛋白粉,研究酶解条件对鱼蛋白起泡性的影响。首先通过单因素试验研究了底物浓度(w/v)、加酶量(w/w)、水解时间、p H值、水解温度对鱼蛋白起泡性的影响,在单因素试验的基础上设计响应面试验,探究各因素及其交互作用对鱼蛋白起泡性的影响,优化酶解条件。结果表明:经木瓜蛋白酶水解得到产物的起泡性较好,优化的酶水解条件为:底物浓度5.65%,加酶量1.47%,p H值8.04,水解温度56.5℃,水解时间3.0 h,此时起泡性为57.3%。     

面筋蛋白酶解增溶及其乳化性能的研究

木瓜蛋白酶水解面筋蛋白可提高水溶性和改善乳化性能，适宜的水解条件为：酶解温度55℃、酶解pH值3,0、酶液浓度1．0％、底物浓度20％、水解时间3h-4h。水解度控制在8％～15％，可使酶解面筋蛋白在广泛pH范围，特别是等电点附近，均具有优良的水溶性和乳化性能。     

草鱼酶解条件的研究

采用木瓜蛋白酶水解草鱼鱼蛋白,采用单因素试验考察各因素对水解效果的影响,通过正交试验确定水解的最佳条件.实验结果表明,木瓜蛋白酶水解草鱼的最佳条件是:酶浓度为2.0％,底物浓度为3.0％,酶解时间为4h,pH为7.0,酶解温度为60℃,在此条件下草鱼的水解度可达到45.93％.     

玉米蛋白粉水解工艺的研究

以玉米蛋白粉为原料,以水解度为检测指标,采用枯草芽孢杆菌发酵和木瓜蛋白酶水解相结合的方法制备高水解度的玉米多肽.研究结果表明,枯草芽孢杆菌发酵玉米蛋白粉的最佳条件为:选择菌龄为14 h的种子液,接种量为12％,发酵培养基的初始pH值为7.5.37℃培养24h,玉米蛋白粉水解度达12.85％;木瓜蛋白酶酶解玉米蛋白粉发酵液的最佳条件为:酶与底物比为6.0％,pH值为6.0,55℃条件水解4h,玉米蛋白粉水解度可达23.69％.     

脱脂蛋黄蛋白粉酶水解实验研究

蛋黄蛋白粉是提取药用卵磷脂生产的副产物,用酶解方法将蛋黄蛋白转化为氨基酸或寡肽是回收利用脱脂蛋黄蛋白粉的重要途径之一.从研究水解反应入手,通过单因素试验和正交优化试验研究胃蛋白酶的最佳水解条件,考察了底物浓度、水解时间、反应温度、pH、酶浓度对脱脂蛋黄蛋白粉水解度的影响,然后根据正交试验结果对胃蛋白酶胰蛋白酶组合水解进行研究.研究结果表明,胃蛋白酶水解的最佳工艺条件是:温度为38 ℃,pH为2.0,底物浓度为5％,酶浓度为2％,水解时间为4h,此条件下水解度为15.76％.胃蛋白酶-胰蛋白酶组合酶水解的最佳工艺条件是:先加胃蛋白酶水解4h,而后调节pH为7.5,温度55℃,再加入浓度为0.5％的胰蛋白酶水解4h,此时水解度高达20.41％,明显高于胃蛋白酶单酶水解.     

蛋白酶水解豆渣制备大豆肽的研究

以大豆豆渣为原料,分别采用木瓜蛋白酶、碱性蛋白酶、中性蛋白酶对大豆豆渣进行水解制备大豆肽.研究了3种蛋白酶在不同温度、pH值、水解时间、酶浓度下水解大豆豆渣的最适酶反应条件,以及水解产物对酸豆乳发酵的影响.结果得出,实验豆渣蛋白质含量为10.4 g/(100 g);木瓜蛋白酶的最适水解条件是底物质量分数5％,酶浓度20 000 U/g,水解温度为50℃,pH7,水解6h,最大水解度可达87.31％;碱性蛋白酶的最适水解条件是底物质量分数5％,酶浓度15 000 U/g,水解温度为55℃,pH9,水解3h,最大水解度可达91.23％;中性蛋白酶的最适水解条件是底物质量分数5％,酶浓度15 000 U/g,水解温度为45℃,pH7,水解8h后达到最大水解度,最大水解度可达81.42％.     

木瓜蛋白酶水解豌豆蛋白的工艺研究

研究木瓜蛋白酶对豌豆蛋白的水解作用,分析了酶量、底物浓度、温度、pH、水解时间因素对水解度的影响,确定木瓜蛋白酶水解豌豆蛋白制备豌豆多肽的最佳水解条件为:酶浓度8%(E/S质量比),底物浓度7%(固液比).反应温度65℃,反应时间3.5 h,pH6.5,并利用高效液相色谱法测定豌豆多肽分子量.试验结果表明,当水解度为30%时,豌豆多肽混合物分子量80%集中在500u左右.     

中性蛋白酶水解核桃蛋白工艺

研究中性蛋白酶对核桃蛋白的水解作用,分析pH、温度、水解时间、底物浓度、加酶量对水解度的影响,并采用正交试验对其进行优化。确定中性蛋白酶水解核桃蛋白制备核桃多肽的最佳水解条件为pH6.0、温度40℃、水解时间3.0 h、底物浓度0.7%、加酶量7 501 nkat(以每克底物计),在此条件下核桃蛋白质水解度为48.53%。     

饲用鱼蛋白肽生产工艺研究

以水解度作为指标,研究了碱性蛋白酶水解鱼粉废水中鱼蛋白制备饲用蛋白肽的工艺条件.考察了酶用量、酶解温度、pH值、酶解时间和底物质量分数等因素对蛋白质水解度的影响.通过正交试验对工艺条件进行优化,确定了最适工艺条件为:底物质量分数16％,振荡速度130 r/min,碱性蛋白酶用量为鱼粉废水中蛋白质的1.0％,酶解温度为60℃,pH值为8.5,反应时间为4.5h.在此最佳条件下得到具有浓郁鱼腥香味,水解度为25.06％的饲用鱼蛋白肽产品.     

玉米功能多肽的制备

文章研究了木瓜蛋白酶对玉米蛋白进行水解制备玉米多肽,以水解度(DH)作为检测标准,通过正交试验确定了玉米肽的最佳水解条件:水解温度为55℃,pH值为7.5,底物浓度为6.0％,加酶量4.0％.在最优条件下水解时间3.5h后水解液的水解度(DH)为14.15％.     

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.     

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     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.