中国曲中凝乳酶高产菌株的筛选及产酶条件的研究

目的:从中国曲中筛选凝乳酶高产茵株以代替小牛皱胃酶作凝乳剂.方法:采用酪蛋白平板进行初筛,测定茵株发酵产酶活力并进行复筛,研究其产酶发酵条件.结果:经多次复筛选育出1株高产凝乳酶活力茵株 Rhizopus arrhizus F34.碳源种类对该菌株产酶影响较大,无机氮源对产酶有抑制作用;MgSO4、FeSO4、ZnSO4对产酶也有较大的抑制作用,CaC12、KC1有利于凝乳酶的产生;pH、发酵温度和发酵时间对F34菌株产酶影响显著.结论:F34菌株产凝乳酶的最佳发酵培养基是:米粉麸皮水解液4.5%、豆粉水解液4.0%、CaC12 0.3%、KC10.5%;最适发酵条件:初始pH 4.5,发酵温度34℃,培养时间60 h.     

解淀粉芽孢杆菌产凝乳酶发酵条件的优化

为了进一步提高解淀粉芽孢杆菌(Bacillus amyloliquefaciens)发酵产凝乳酶的活力,采用单因素和正交试验设计,对影响解淀粉芽孢杆菌凝乳酶活力的培养温度、摇床转速、培养基初始pH及发酵时间等主要因素进行了优化组合试验,确定最佳发酵条件。结果表明:摇床转速对解淀粉芽孢杆菌凝乳酶活力影响最大,其次是发酵时间,培养基初始pH的影响较小。单因素和正交试验结果确定的最佳发酵条件为:在100mL三角瓶中装30mL发酵培养基,接种量3%,培养温度39℃,培养基最初pH为6.0,发酵时间为14h,摇床转速为120r/min,凝乳酶活力可达923.1Su/mL。     

根霉产凝乳酶的固态发酵条件优化

对根霉产凝乳酶固体发酵条件进行研究。通过单因素分析和响应面试验设计,确定根霉产凝乳酶的发酵条件及发酵培养基的最佳组成为:24℃发酵7d;麸皮与江米质量比为0.96:1、培养基固液比(m/V)为0.99:1、奶粉添加质量分数为0.81%,所产的凝乳酶活力达到72.92SU/mL。     

响应面法优化微小毛霉固态发酵生产凝乳酶工艺研究

采用麦麸培养基进行固态发酵,以研究发酵条件对产酶活力的影响,在此基础上应用Plackett-Burman、最陡爬坡实验和Box-Behnken实验设计,对微小毛霉的固态发酵培养基进化以达到最佳产酶量。实验结果表明,最佳发酵条件为:发酵时间5d,发酵温度30℃,固液比值0.75,接种量为3份,测得凝乳酶酶活为828U/mL。并且当麸皮质量为15.50g、(NH4)2SO4质量为0.15g、KH2PO4质量为0.08g时,微小毛霉产凝乳酶活力达到1200U/mL。较未优化前活力提高了66.67%。     

红曲米中凝乳酶产生菌的筛选及液态发酵条件的优化

红曲米是我国古代流传下来的一种传统添加剂,红曲米中微生物所产凝乳酶具有凝乳作用.采用酪蛋白平板法和Arima时间法筛选出了1株产生凝乳酶能力强的菌株M5.通过正交试验,对该霉菌产凝乳酶发酵条件进行了初步优化, 结果表明,PDA 培养基是该霉菌产凝乳酶的最佳培养基,最佳培养条件为温度30℃、转速为160 r/min、振荡培养72 h,凝乳活力可达到150.6 SU.     

解淀粉芽孢杆菌GSB a-1产凝乳酶培养基组成的优化

从甜酒曲中分离筛选得到1株解淀粉芽孢杆菌菌株GSBa-1,为了提高该菌株液态发酵产凝乳酶的能力,采用单因素实验和响应面法优化其产酶培养基组成。通过单因素实验分析了碳源、氮源、金属盐、磷源对菌株GSBa-1产凝乳酶的影响,并采用响应面法对产酶培养基中麦芽糖、蛋白胨和酵母浸粉含量3个主要因素的优化组合进行了定量研究,确定解淀粉芽孢杆菌GSBa-1产凝乳酶的优化培养基组成为:麦芽糖1.93 g/L、蛋白胨10.89 g/L、酵母浸粉2.15 g/L。在此优化培养基培养条件下,该菌株产凝乳酶活力可达(562.57±7.67)Su/m L,接近理论预测值537.10 Su/m L,且平均误差为4.53%。优化后解淀粉芽孢杆菌GSBa-1产凝乳酶活力比基础培养基提高了1.88倍。     

一株产凝乳酶细菌的分离与鉴定

利用酪蛋白和麸皮培养基从奶牛场土壤中分离出高凝乳活力,低蛋白水解力的细菌.获得22株产凝乳酶细菌,其中菌株BB-23产凝乳酶活力高而蛋白水解活力低,经形态观察、生理生化和16S rRNA鉴定为枯草芽孢杆菌(Bacillus subalis),该菌株在麸皮培养基发酵72h后产凝乳酶活力达73.80SU/mL,蛋白水解力为16.01U.     

豆粕水解液为原料根霉产纤溶酶液体发酵培养基的优化

以豆粕水解液为原料,研究根霉产纤溶酶液体发酵培养基的组成.实验结果表明,豆粕的最适水解时间为1.5 h,麸皮水与豆粕水解液的最适体积比例为2:3,金属离子对酶活力提高无显著作用,最适培养基配方是:5%麸皮水,6%豆粕水解液,0.1%氯化铵,0.2%硝酸钠,2.5%胰蛋白胨,初始pH4.3,酶活力为177.62 U/mL.     

影响解淀粉芽孢杆菌GSBa-1产凝乳酶的因素及发酵条件优化研究

为了提高解淀粉芽孢杆菌GSBa-1发酵产凝乳酶活力,通过单因素试验并采用Plackett-Burman试验设计对影响该菌株发酵产酶条件的6个因素进行评价,筛选出具有显著影响作用的3个因素即发酵温度、发酵时间和装液量,然后通过响应面法探讨此3个主要因素的最优发酵参数水平,获得最佳的发酵产酶条件。结果表明,解淀粉芽孢杆菌GSBa-1发酵产凝乳酶的最佳工艺条件为:发酵温度36℃,发酵时间75h,装液量40%,初始p H为培养基自然p H(6.85),接种量4%,摇床转速160r/min。此条件下解淀粉芽孢杆菌GSBa-1发酵产酶活力为742.42 Su/m L。解淀粉芽孢杆菌GSBa-1发酵产凝乳酶活力经发酵条件优化后得到显著提高,该菌株的发酵产酶及在干酪生产中的应用具有良好的产业化开发前景。     

响应面法优化红曲米中凝乳酶高产菌株的发酵条件

对从红曲米中分离得到的产凝乳酶能力强的菌株M5传代菌株的液态发酵培养基及产酶条件进行优化。首先进行单因素实验得到适宜的氮源为(NH4)2SO4、酪蛋白,无机盐为FeSO4、KH2PO4,适宜的接种量为1%,培养温度为30℃,培养时间为5d,发酵培养基初始pH为6.0。在此基础上通过Plackett-Burman实验筛选出对酶活影响显著的三个因素:(NH4)2SO4含量、培养时间和培养温度。再用Box-Behnken响应曲面实验对三个显著因素进行优化。结果表明,产酶的最佳培养基组分:(NH4)2SO40.53%、FeSO40.05‰、KH2PO40.05%、干酪素0.5%、葡萄糖2%、接种量1%。最佳发酵条件为:培养温度31.3℃、摇床转速为180r/min、培养时间113h、pH6.0。基于响应曲面优化的产凝乳酶培养基组成与发酵条件效果显著,供试菌株M5传代菌株所产凝乳酶活性由45.34SU/mL提高到190.68SU/mL。     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

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 Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.     

National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the "13~(th) Five-Year Plan"

In Apri Commi major p Plan＂ （h 2014, the National Development and Reform ssion issued an announcement for selection of reliminary research projects for the ＂13th Five-Year ereafter referred to as ＂The Announcement＂）     

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 latest scientific     

Contamination of animal feed and food from animal origin with mineral oil hydrocarbons

Oils and fats used for the production of animal feed can become contaminated with mineral oil material originating from gas oils (C₁₈-C₃₅) or synthetic oils (poly alpha olefins, C₂₅ to beyond C₄₅). An important cause is assumed to be the discharge of waste oils, such as motor oil and hydraulic oils. Mineral oil material was analysed by on-line LC-GC-FID directly in the fat or in a raw extract from animal feed or foodstuffs. In Switzerland in summer/autumn 1999 concentrations in oils and fats for feed production were often found to be between 100 and 1000mg/kg. In the feeds, the average concentration was around 100mg/kg with values ranging up to a maximum of 1000mg/kg; few samples were free of contamination. In animal body fat, the average concentration determined in summer 1999 was 25mg/kg, with a maximum of 150mg/kg, although in samples from December 1999, contamination was substantially lower. In the fat phase of eggs, the average concentration was 30mg/kg, with a maximum of 80mg/kg. Paraffin oil is used for feed production, which may account for part of the contamination problem (e.g. eggs).