藜麦秸秆蛋白的结构和功能性质

以藜麦秸秆为原料,利用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE）、红外光谱和差示扫描量热法（differential scanning calorimetry,DSC）对从藜麦秸秆中提取到的蛋白质结构特性进行表征,并研究温度和pH值对藜麦秸秆蛋白功能性质的影响。结果表明,藜麦秸秆蛋白以中低分子量的蛋白质为主,分子质量主要分布为29.0ku～44.3ku和小于14.3ku;热学特性研究结果显示：藜麦秸秆蛋白热稳定性较好,其变性温度为132.72℃,变性焓变为7.82 J/g;游离巯基和二硫键含量分别为10.21 μmol/g和23.57 μmol/g,藜麦秸秆蛋白二级结构中β-转角相对含量最高,为36.42%,α-螺旋含量为25.19%,β-折叠含量为25.91%,无规则卷曲含量为12.48%。温度为60℃时,藜麦秸秆蛋白的溶解性、吸水性和起泡性最佳,分别为53.61%、3.11 g/g和40.24%;pH值为9时,溶解性、吸水性和起泡性最好,分别为46.37%、3.34 g/g和40.86%。     

绿豆淀粉工艺废水中蛋白质的功能性质

对绿豆淀粉工艺废水中蛋白质的功能性质进行研究。结果表明:绿豆淀粉工艺废水蛋白在40℃、p H 9时溶解性最好;持水性在40℃条件下最好,达到362.63%;持油性随温度变化在150%~170%之间变化不明显;起泡性和泡沫稳定性及乳化性和乳化稳定性随蛋白质量浓度增加而上升;电泳测定结果表明:蛋白分子质量分别为62.5、46.1、27.0、20.9、16.2 k D;氨基酸分析结果表明:蛋白总氨基酸含量为616.802 mg/g,必需氨基酸含量为233.960 mg/g,蛋氨酸为第一限制性氨基酸;蛋白二级结构中α-螺旋含量为39.68%,β-折叠含量为20.13%,β-转角含量为16.56%,无规则卷曲含量为23.71%;特征分解温度区间为220~360℃。     

蚕蛹水溶性蛋白营养学评价及理化性质分析

对蚕蛹水溶性蛋白进行了营养学评价,并对其二级结构和热特性进行了分析。结果表明:蚕蛹水溶性蛋白中氨基酸种类齐全,必需氨基酸占总氨基酸含量的41.2%,氨基酸评分为54.1,其限制性氨基酸分别为:亮氨酸(第一限制性氨基酸)、异亮氨酸(第二限制性氨基酸)、缬氨酸(第三限制性氨基酸)和苏氨酸(第四限制性氨基酸),是一种值得开发利用的蛋白资源。蚕蛹水溶性蛋白的二级结构含量为:α-螺旋20.9%、β-折叠24.1%、β-转角19.2%和无规则状态36.4%,其热变性温度为60.7℃。     

大鲵黏液糖蛋白的提取工艺优化及纯化表征

本文以丽水人工养殖大鲵的黏液为原料,优化大鲵黏液粗糖蛋白提取工艺并进行纯化表征。基于单因素实验,以料液比、温度、提取液浓度以及提取时间为考察因素,粗糖蛋白得率为指标,采用响应面法优化提取工艺,得到最佳提取条件为:料液比1:30.5 g/mL、提取温度51 ℃、提取液浓度0.32 mol/L、提取时间5.2 h,大鲵黏液粗糖蛋白得率最高为5.22%±0.71%。纯化得到大鲵黏液糖蛋白（MGP）,经表征分析,测定其达到电泳纯,分子量约为29 kDa;MGP中必需氨基酸及药用氨基酸含量分别为37.21 g/100 g和33.39 g/100 g;MGP具有典型的糖蛋白结构的紫外全波长吸收图像;含有O型糖肽键,吡喃糖环结构和β-糖苷键,β-折叠结构占蛋白质二级结构的87%,为后续深入探究大鲵黏液糖蛋白生物活性提供一定基础。     

椰子蛋白化学结构和热稳定性研究

摘 要：目的：研究椰子全粉中蛋白的结构和热稳定性，为深度开发椰子蛋白资源提供理论基础。方法：采用碱提酸沉法提取椰子全粉中蛋白质，酸水解法结合氨基酸自动分析仪测定氨基酸组成，利用傅里叶变换红外光谱法分析蛋白二级结构，热重分析仪分析蛋白热降解温度，纳米粒度分析仪研究溶液中蛋白颗粒的Zeta电位和粒径大小。结果：椰子蛋白含有18种氨基酸，富含精氨酸和谷氨酸，8种必需氨基酸含量丰富、比例合理，是营养良好的蛋白质来源。椰子蛋白的二级结构以稳定态的β-折叠为主，含量达44.2%，椰子蛋白降解起始温度273.12 ℃，峰值温度332.91 ℃，至最终实验设定温度780 ℃时仍有25.9%残余未热降解完全，60 ℃时椰子蛋白溶液Zeta电位和粒径与25 ℃无显著变化。这些表明椰子蛋白具有良好的热稳定性，可为椰子蛋白广泛利用提供了基础可行性。     

白灵菇蛋白提取及功能特性和结构分析

以脱脂后的白灵菇为原料,采用超声波-微波辅助碱法提取白灵菇蛋白。结果表明：白灵菇蛋白质最佳提取条件为提取温度50?℃、超声波功率500?W、微波功率24?W、NaOH溶液浓度0.09?mol/L、料液比1∶30（g/mL）、提取时间0.8?h,蛋白得率为（10.28±0.62）%。对白灵菇蛋白功能特性和结构进行研究,结果表明：白灵菇蛋白在70?℃、pH?8.5时溶解度最大;白灵菇蛋白的持水性在60?℃时最好,为（325.27±2.40）%,持油性在50?℃时达到最佳,为（189.60±2.58）%;起泡性和起泡稳定性以及乳化性和乳化稳定性随蛋白质质量浓度的增加而缓慢增加,超高效液相色谱分析结果表明,白灵菇蛋白总氨基酸含量为810.40?mg/g,必需氨基酸含量为322.86?mg/g,组氨酸是第1限制性氨基酸;圆二色光谱分析结果表明白灵菇蛋白二级结构中α-螺旋相对含量为53%,β-折叠相对含量为11%,β-转角相对含量为14%,无规卷曲相对含量为23%,白灵菇蛋白分子质量分布为48.9、26.3、16.4、10.9?kDa,傅里叶变换红外光谱分析结果显示其蛋白特征官能团吸收峰明显。     

玉米胚芽蛋白的分离及物化特性研究

采用碱溶酸沉法提取玉米胚芽分离蛋白,利用氨基酸分析和电泳分析胚芽蛋白的氨基酸组成和有效亚基组成。凝胶层析分离玉米胚芽蛋白组分,并对各组分进行热变性温度及圆二色谱分析。氨基酸分析结果表明,玉米胚芽蛋白中谷氨酸和赖氨酸含量较高,其它氨基酸含量较均衡。还原的十二烷基硫酸钠-聚丙烯酰胺电泳(SDS-PAGE)图主要有九条谱带,其分子量依次为87.988、76.320、69.650、53.649、48.546、38.164、34.337、32.294和24.483 kDa。凝胶层析分离获得两个蛋白组分。差示扫描量热仪(DSC)分析表明分离所得两个组分的干粉变性温度分别为97.37℃和98.95℃,圆二色谱(CD)分析表明两个蛋白组分的二级结构主要为β-折叠和无规卷曲。     

辣木叶水溶性蛋白的超声-微波萃取及其性质研究

研究辣木叶中可溶性蛋白的提取工艺及其性质。采用超声-微波协同萃取方法提取辣木叶中可溶性蛋白,在单因素实验的基础上,通过Box-Behnken中心组合实验确定最佳工艺参数,并对蛋白质氨基酸组成进行分析。实验结果表明:当料液比1∶160(g/m L),微波功率40 W,提取时间127 s,p H11,在此工艺条件下,辣木叶蛋白得率为40.11 mg/g。氨基酸分析表明,辣木叶可溶性蛋白中必需氨基酸含量为280.7 mg/g,含硫氨基酸含量较高,苏氨酸为第一限制性氨基酸。差示扫描量热仪(DSC)分析表明辣木叶可溶性蛋白的变性温度为113.7℃。     

响应面法优化黑木耳蛋白质的提取工艺

以黑木耳为原料,采用酶法进行前处理后用超声波辅助碱法提取黑木耳蛋白质,获得黑木耳蛋白质的最优提取工艺条件。以蛋白质得率为评价指标,进行单因素试验,并采用Box-Behnken响应面法优化黑木耳蛋白提取工艺。结果表明,纤维素酶和木聚糖酶混合酶解最佳前处理条件为:酶解温度50℃、酶解pH 4、酶解时间2 h、酶添加量(加酶量/木耳干质量)0.8%。黑木耳蛋白最佳提取条件为料液比1︰91(g/mL)、超声温度49℃、超声时间40min。最佳提取条件下黑木耳蛋白得率为4.84%。试验表明经酶法前处理后采用超声波辅助碱法能显著提高黑木耳蛋白质提取效率。     

超声波对牡丹籽粕蛋白质碱提取工艺及氨基酸组成的影响

以脱脂牡丹籽粕为原料,通过单因素实验和正交实验考察超声波对牡丹籽粕蛋白质碱提取工艺条件的影响。结果表明:常规碱提取的最佳工艺条件为料液比1:15(g:mL)、溶液pH值11、提取温度55℃、提取时间100 min,在该条件下蛋白质的提取率为81.49%;超声辅助碱提取的最佳工艺条件为料液比1:10(g:mL)、溶液pH值11、超声功率180 W、超声温度55℃、超声时间100 min,在该条件下蛋白质的提取率达87.34%。与常规碱提取相比,超声辅助碱提取的提取率提高了7.17%,碱液消耗降低了33.33%。同时,超声辅助碱提取的牡丹籽粕蛋白的各种氨基酸含量均高于常规碱提取的牡丹籽粕蛋白,氨基酸总含量达95.049 mg/100 g,纯度提高14.49%。     

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.