豆豉生产中高产蛋白酶的米曲霉诱变及产酶条件优化

为了提高豆豉发酵品质,采用紫外和亚硝基胍方法对产蛋白酶菌株的米曲霉进行诱变处理,以最佳诱变条件筛选得到突变菌株,使其蛋白酶活力提高38.01%,且菌株能够保持较好的遗传稳定性。进一步利用响应面分析法研究培养温度、湿度和时间对该菌株产蛋白酶活力的影响,得到最佳条件为:培养温度42.8℃、湿度84.5%、时间66.6 h,此条件下产酶模型预测值为518.63 U/g,验证实验中产酶活力值为507.87 U/g,表明预测值与实验值拟合良好,达到设计要求,显示诱变所得米曲霉突变株发酵产蛋白酶能力有较大提升。     

高产Monacolin K红曲霉菌株选育及发酵条件的优化

对产Monacolin K的红曲霉菌株进行了复合诱变后的筛选和发酵条件优化。通过紫外-亚硝酸钠复合诱变,得到一株高产Monacolin K的菌株3.991-7。通过单因素试验,以Monacolin K的产量为指标,确定出最佳发酵条件：接种量7%,pH值为4.5,培养温度为25 ℃,培养时间为10 d。在此最佳条件下,诱变菌株固态发酵后的Monacolin K的产量为9.06 mg/g。     

紫外线与微波复合诱变选育高产脂肪酶菌株的研究

研究选育高产脂肪酶菌株。采用紫外线诱变、微波诱变和紫外微波复合诱变出发菌株H3,测定比较酶活,确定最佳诱变效果。结果表明,出发菌株经紫外线和微波诱变后,所产脂肪酶的最高酶活分别为57.984 U/m L和57.1 U/m L,比出发菌株H3提高了38.3%和36.2%,经微波辐射40 s和紫外线照射80 s的复合诱变菌株M3产酶活力最高,达61.6 U/m L,比出发菌株H3提高了46.85%。     

高糖化力白曲霉的复合诱变及固态发酵条件优化

采用紫外线及常压室温等离子体（ARTP）复合诱变技术对白曲霉（Aspergillus candidus）Nz 3.602进行诱变选育。对诱变致死率进行测定,确定最佳诱变条件为：15 W紫外灯照射12 min,ARTP处理40 s。对突变菌株进行透明圈法初筛、糖化力测定法复筛,最终得到产酶能力较高的突变菌株B5。其糖化酶酶活为1 050.32 U/g,较出发菌株糖化酶酶活提高85.53%,并且遗传稳定性较好。以菌株B5为研究对象,经单因素试验和响应面分析法对其固态发酵条件进行优化,最佳固态发酵条件为：糠壳添加量15%,原料含水量70%,接种量12%,培养时间5 d,培养温度30 ℃。该条件下糖化酶酶活为（1 254.17±6.14） U/g,比优化前提高了19.41%。     

高产蛋白酶菌株的分离鉴定及诱变

目的:从豆豉中分离出高产蛋白酶的菌株并进行紫外诱变,以提高菌株的产蛋白酶能力.方法:采用酪蛋白平板法,初步筛选出一些产蛋白酶菌株,通过比较发酵后蛋白酶活力,筛选出一株产蛋白酶活力最高的菌株,鉴定其菌种,对该菌株进行紫外诱变,并对诱变后的菌株进行筛选,最后得到一株产蛋白酶活力最高的菌株.结果:分离鉴定后得知菌株B为地衣芽孢杆菌,产蛋白酶活力为2360.80U/mL.最佳诱变时间为120s,菌落致死率为66.68％,得到的高产蛋白酶菌株为B-14,其蛋白酶活力为2922.90U/mL,诱变后菌株产蛋白酶活力提高了23.81％.结论:通过筛选、诱变成功选育出高产蛋白酶的菌株B-14.     

黑曲霉原生质体诱变及其产纤维素酶条件研究

采用紫外、硫酸二乙酯及复合诱变3种方法对黑曲霉原生质体进行诱变育种,以提高其酶活。结果表明,采用复合诱变效果最好,复合诱变所得菌株的酶活比出发菌株大幅度提高;应用单因素实验优化突变菌株的产酶条件,其最佳产酶条件培养基为:5%蔗糖、1.4%蛋白胨、0.2%磷酸二氢钾、0.05%硫酸镁,在250 mL摇瓶中装液60 mL,10%接种量、29℃下200 r/min培养96 h,酶活达到最大。     

双酶水解鸡骨泥的工艺优化

对鸡骨泥进行酶水解,经筛选确定中性蛋白酶和Flavourzyme复合风味酶的组合能有效酶解鸡骨泥。经正交试验分析,确定酶解的最佳工艺为:酶解温度50℃、pH值8.5、中性蛋白酶和Flavourzyme复合风味酶的添加量分别为0.75%和1.50%、底物浓度5%、水解时间2.5h。在该条件下酶解效率最高,水解度和氮收率分别为37.11%和92.50%,酶解产物澄清无苦味及腥味,且游离氨基酸含量显著增加。     

一株高产纳豆激酶菌株的筛选及其发酵条件的优化

通过紫外诱变、纤维蛋白原平板初筛、复筛得到了一株高产纳豆激酶的纳豆芽孢杆菌菌株。研究液体发酵产纳豆激酶的最佳条件,结果表明最佳培养基为营养肉汤,最佳培养时间为24h,最佳培养温度30℃。在优化条件下,发酵液酶活达640U/ml。该菌株的酶活比原始菌株酶活提高了258%。     

不同蛋白酶对红鳍笛鲷鱼排酶解液风味影响

以红鳍笛鲷鱼排为原料,分别采用中性蛋白酶、碱性蛋白酶、木瓜蛋白酶和风味蛋白酶4种酶水解,通过氨基酸组成分析、感官评价及电子舌对酶解液的滋味进行评价。结果表明：风味蛋白酶酶解液的水解度及多肽含量最高,分别为29.14%、4.27 g/100 g;氨基酸组成分析表明风味蛋白酶酶解液的氨基酸总含量最高。感官评价结果表明,4种蛋白酶酶解液中风味蛋白酶酶解液风味较好,苦味不明显,总体呈味鲜美浓郁。电子舌测定结果表明,中性蛋白酶与风味蛋白酶的酶解液最接近鲜味参比溶液。因此最终确定风味蛋白酶是制备红鳍笛鲷鱼排呈味肽的最佳用酶。     

诱变米曲霉发酵高温豆粕菌种筛选及发酵工艺优化

以高温豆粕为原料,以酶活力为指标,通过紫外诱变和遗传稳定性试验选育出遗传性能稳定的蛋白酶高产的米曲霉诱变菌株;以水解度为指标,优化发酵工艺条件,进一步提高高温豆粕的水解度。紫外诱变条件为20W紫外灯35cm处辐照180s,得出最佳的发酵培养基组成为葡萄糖3%和高温豆粕12%;采用单因素试验方法确定的培养条件为:发酵温度30℃、发酵时间48h、接种量9%、摇床速度160r/min和起始pH值5.5,此条件下高温豆粕的水解度可达到24.05%,比优化前提高了3.86%。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

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.