恩施鱼塘坝玉米硒富集及玉米肽抗氧化活性研究

为了探究恩施鱼塘坝地区硒资源的分布特点,土壤因素对玉米中硒含量的影响以及硒含量和玉米肽(CPs)抗氧化活性的关系,本文采用玉米良种(湘玉十号),在鱼塘坝附近选取16个不同地点种植,并分两季采收,利用原子荧光法对玉米中蛋白质、多糖中硒含量进行分析,同时对种植地土壤样本的硒含量和p H值进行了测定。通过Hep G2人体肝癌细胞模型对高硒CPs以及低硒CPs的抗氧化活性进行研究。结果表明:所有玉米种植地土壤均达到富硒土壤标准(0.4 mg/kg),但其生长的玉米中硒含量存在较大差异,玉米对硒的富集受到土壤硒含量、种植时间以及p H值的共同影响;玉米中蛋白和多糖具有很高的硒含量。高硒玉米和低硒玉米制成的玉米肽均表现出较好的抗氧化能力,但前者显著高于后者(P0.05),在Hep G2细胞抗氧化模型中,500μg/m L浓度为玉米肽最佳抗氧化浓度;与较低硒玉米肽处理组相比,经高硒玉米肽预处理的细胞存活率增加了24.16%。综上所述,p H低于5的土壤对玉米吸收硒的能力有严重抑制作用,弱碱性土壤更适合玉米对于硒的利用,且种植时间较长的老玉米硒含量更高;富硒玉米肽的抗氧化能力显著高于低硒玉米肽。     

富硒玉米肽对四氯化碳致小鼠急性肝损伤的保护作用

研究富硒玉米肽对四氯化碳(Carbon tetrachloride,CCl4)诱导的小鼠肝损伤的保护作用。将健康的雄性昆明小鼠70只,随机分成7组:正常对照组、CCl4模型组、富硒玉米肽低、中、高剂量组(100、200、400mg/kg·bw)、普通玉米肽组(200 mg/kg·bw)、水飞蓟素阳性对照组(50 mg/kg·bw),每组10只。测定比较血清中谷丙转氨酶(ALT)活力、谷胱甘肽(GSH)、三酰甘油(TG)含量,同时测定肝组织中丙二醛(MDA)、谷胱甘肽(GSH)的含量及超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活力,肝脏指数,并观察肝组织病理学变化。结果显示富硒玉米肽低、中、高剂量组均能极显著抑制CCl4致肝损伤小鼠血清ALT活性和TG含量的升高、GSH含量的降低(P0.01);均能极显著提高肝组织中GSH含量和SOD、GSH-Px活力,并降低肝组织中MDA的含量(P0.01),极显著降低由于肝损伤引起的肝脏肿大(P0.01),改善肝组织损伤程度,并存在剂量效应关系。富硒玉米肽高剂量组的护肝效果与50 mg/kg·bw的水飞蓟素相当,相同剂量的富硒玉米肽的保肝作用极显著优于普通玉米肽(P0.01)。结果表明富硒玉米肽对CCl4所致小鼠急性肝损伤有显著的保护作用,且与普通玉米肽相比,富硒玉米肽的有效保肝剂量显著降低。     

富硒大米肽体内抗氧化活性研究

目的:比较普通大米肽、富硒大米肽和硒代蛋氨酸的体内抗氧化活性。方法:将60只老龄(12月龄)雄性昆明小鼠和10只少龄(1月龄)雄性昆明小鼠分成7组(每组10只):老龄模型组(M组)、少龄对照组(YC组)、普通大米肽组(400 mg/kg·bw,Ⅰ组)、富硒大米肽组(400 mg/kg·bw,Ⅱ组)、硒代蛋氨酸组(2.5μg/kg·bw,Ⅲ组)、富硒大米肽+硒代蛋氨酸组(200 mg/kg·bw+1.225μg/kg·bw,Ⅳ组)和白藜芦醇组(10 mg/kg.bw,PC组),其中富硒大米肽组、硒代蛋氨酸组以及富硒大米肽+硒代蛋氨酸组中的硒含量一致,连续灌胃30 d。结果显示:与M组相比,YC组、Ⅱ组、Ⅲ组、Ⅳ组、PC组小鼠血清中超氧化物歧化酶(SOD)活性极显著提高(p0.01);YC组、Ⅰ组、Ⅳ组的还原型谷胱甘肽(GSH)含量显著增加(p0.05),Ⅱ组和PC组GSH含量极显著增加(p0.01);YC组、Ⅱ组、PC组的过氧化氢酶(CAT)活性显著增加(p0.05);Ⅲ组、Ⅳ组的肝匀浆中谷胱甘肽过氧化物酶(GSH-Px)活性显著提高(p0.05),Ⅱ组的GSH-Px活性极显著增加(p0.01);Ⅱ组、Ⅳ组、PC组的T-AOC显著增加(p0.05);YC组、Ⅱ组的丙二醛(MDA)显著减少(p0.05),PC组的MDA极显著减少(p0.01);YC组、PC组的GSH显著增加(p0.05),Ⅱ组的GSH极显著增加(p0.01),以及胸腺、脾脏指数等指标均有不同程度地改善。其中所有指标以富硒大米肽组效果最好,抗氧化活性显著高于同剂量的普通大米肽,大多数指标也显著优于同等硒含量的硒代蛋氨酸组。结论:富硒大米肽中的硒与肽对增强抗氧化能力有一定的增效作用。     

富硒大豆低聚肽的抗氧化活性研究

研究了富硒大豆低聚肽在抗氧化方面的作用。将3周龄SD雄性大鼠90只,随机分为6组,即Ⅰ(对照组)、Ⅱ(大豆蛋白组)、Ⅲ(大豆多肽组)、Ⅳ(亚硒酸钠组)、Ⅴ(大豆低聚肽组)、Ⅵ(富硒大豆低聚肽组),在实验环境下,对各组饲喂低硒基础饲料的同时,对第Ⅱ组口腔灌喂大豆蛋白,对第Ⅲ组口腔灌喂大豆多肽,对第Ⅳ组口腔灌喂亚硒酸钠,对第Ⅴ组口腔灌喂大豆低聚肽,对第Ⅵ组口腔灌喂富硒大豆低聚肽,第Ⅰ组口腔灌喂同体积的饮用水。饲喂4周,处死后分别测定各实验大鼠血清和肝脏中的MDA(丙二醛)含量、GSH-Px和SOD活性。结果显示:第Ⅱ、Ⅲ、Ⅴ、Ⅳ、Ⅵ组均能降低血清和肝脏中MDA的含量,提高GSH-Px和SOD活性,但第Ⅱ、Ⅲ组作用不显著,第Ⅴ组作用显著,第Ⅳ、Ⅵ组作用极显著。各组样品对血清和肝脏中MDA含量和GSH-Px活性的影响效果趋于一致,但对血清SOD活性的影响明显强于对肝脏SOD活性的影响,实验结果说明富硒大豆低聚肽具有抗氧化功能,这种功能主要通过降低大鼠血清和肝脏中MDA的含量,提高GSH-Px和SOD活性来实现,富硒大豆低聚肽的抗氧化功能要强于无机硒,明显强于不含硒的大豆低聚肽,推测富硒大豆低聚肽中发挥抗氧化功能的主要是微量元素硒。     

亚硒酸钠和硒代蛋氨酸对人结肠腺癌细胞的毒性作用

探讨两种硒化物对人结肠腺癌Caco-2细胞的毒性作用。将Caco-2细胞暴露在不同浓度的亚硒酸钠(SeIV)和硒代蛋氨酸(SeMet)中培养24 h,用Annexin V-FITC/PI双染色法检测在同样浓度的SeIV和SeMet培养下细胞的凋亡率,并设置不做硒处理的空白对照。用MTT法检测细胞存活率;检测细胞培养液中乳酸脱氢酶(LDH)释放率、细胞内的超氧化物歧化酶SOD活力和谷胱甘肽GSH的含量。相同浓度时(0.8μg Se/mL),与对照相比,SeIV诱导细胞凋亡显著率上升(p0.05),SeMet变化不显著。一定浓度的SeIV(≥0.4μg Se/mL)和SeMet(≥40μg Se/mL)与对照组相比均显著降低细胞的存活率(p0.05);随着Se含量的升高细胞的存活率呈下降趋势,SeIV、SeMet的IC_(50)分别为2.56、215.55μg Se/mL。当SeIV浓度为≥0.8μg Se/mL,SeMet浓度为≥40μg Se/mL时,细胞的LDH释放率均显著高于对照组(14.80%)(p0.05)。当SeIV浓度≥4μg Se/mL,SeMet≥4μg Se/mL时,细胞的SOD活性均显著低于对照组(56.76 U/mg prot)(p0.05)。当SeIV浓度≥4μg Se/mL,SeMet浓度为160μg Se/mL时,细胞的GSH含量均显著低于对照组(61.67μg/mg prot)(p0.05)。一定浓度的SeIV和SeMet会使Caco-2细胞产生氧化应激而导致细胞毒性,诱导细胞凋亡。     

HPLC-ICP-MS在线联用分析食品中无机硒和硒氨基酸的形态

以亚硒酸盐(Se(Ⅳ))、硒酸盐(Se(Ⅵ))、硒胱氨酸(Se Cys_2)、硒蛋氨酸(Se Met)、甲基硒代半胱氨酸(Me Se Cys)和硒代乙硫氨酸(Se Et)为硒形态的目标分析物,采用Dionex Ion Pac AS11色谱柱(250 mm×4.0 mm)为分离柱,通过优化流动相的p H、浓度、甲醇含量、流速和色谱柱的柱温等因素对六种目标硒形态分离及不同提取方法对目标分析物提取效率的影响,建立了高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)在线联用同时测定食品中无机硒和硒氨基酸的分析方法。Me Se Cys、Se Met、Se Et、Se(Ⅳ)、Se Cys_2和Se(Ⅵ)的检出限分别为0.25、0.20、0.35、0.15、0.30、0.15μg Se/L;Me Se Cys和Se Cys_2的线性范围为2.0~2500μg Se/L,Se(Ⅳ)和Se(Ⅵ)线性范围为1.2~1200μg Se/L,Se Met和Se Et的线性范围分别是1.5~1500μg Se/L和2.2~2200μg Se/L,各硒形态的线性相关系数均不少于0.9997。将该方法应用于食品中硒形态的分析,其加标回收的回收率为80.8%~106.7%,相对标准偏差(RSDs,n=3)为4.7%~9.6%。方法具有操作简单、方便快速、灵敏度高和环境友好等优点,可满足食品中硒形态定量分析。     

螺旋藻富硒转化含硒蛋白质的鉴定及其抗氧化活性研究

研究富硒螺旋藻(Se SP)培养生物转化含硒蛋白质(Se P)中硒的含量及分布,观察Se P在体外对氧自由基的清除效应。藻体总蛋白(TP)用SDS-PAGE电泳分离后,用电感偶合等离子体质谱技术(ICP-MS)对不同分子量范围蛋白质中的硒含量进行精确定量;通过激光烧蚀(LA)-ICP-MS对纯化含硒藻蓝蛋白(Se PC)硒含量在电泳胶上进行原位检测;用制备SDS-PAGE凝胶电泳分离纯化不同分子量的Se P组份,化学发光方法检测Se P在体外对超氧自由基和羟自由基的清除作用。结果发现,与未富硒培养的螺旋藻(SP)相比,Se SP总蛋白中硒含量提高了32倍,可达805.48μg/g,其中75.81%分布于25 ku以下小分子量含硒蛋白质(LMWSe P)中,LA-ICP-MS证明纯化Se PC亚基含有稳定共价结合活性硒元素,LMWSe P对自由基的直接最大清除率在70%以上。结果提示,利用Se SP培养可转化生产活性Se P,Se SP中低分子量Se P组份是一种具有较高抗氧化活性的天然活性硒资源,其中硒的存在形态、合成转化机制和体内生物活性有待深入研究。     

富硒牡蛎肽的制备及其抗氧化和血管紧张素转化酶抑制活性研究

为开发兼具抗氧化和血管紧张素转化酶(angiotensin converting enzyme, ACE)抑制活性的富硒牡蛎肽，该研究以富硒牡蛎蛋白为原料优化制备富硒牡蛎肽，并对其硒含量、氨基酸组成、抗氧化活性和ACE抑制活性进行评价。结果表明，富硒牡蛎肽的最佳酶解条件为时间4 h、温度37℃、酶底比0.5%、pH 1.0、底物质量浓度7 g/100mL。该条件下制备的富硒牡蛎肽富含与抗氧化和ACE抑制活性相关的疏水性氨基酸和酸性氨基酸，其清除DPPH自由基和ABTS阳离子自由基的EC₅₀值分别为1.365、1.074 mg/mL,并呈现出良好的细胞抗氧化活性(EC50:1.114μg/mL),对HepG2细胞的氧化损伤具有显著的保护作用，且呈量效关系。此外，富硒牡蛎肽的ACE抑制活性较强，这可能与其良好的抗氧化活性具有内在关联性。富硒牡蛎肽具有良好的抗氧化和降血压活性，该研究结果为牡蛎源富硒肽研究奠定了前期基础，为天然富硒营养健康食品的开发提供了理论依据。     

高效液相色谱-电感耦合等离子体质谱法检测富硒苹果中5种硒形态

目的建立高效液相色谱-电感耦合等离子体质谱联用技术(high performance liquid chromatographyinductively coupled plasma mass spectrometry,HPLC-ICP-MS)测定富硒苹果中5种硒形态的方法。方法对样品提取方法、流动相的类型、浓度、p H值等条件进行考察及确定,采用柠檬酸超声提取的方式处理样品,流动相为浓度为5 mmol/L、p H=5.0的柠檬酸溶液。选用Hamiltion PRP-X100阴离子分析柱,色谱进样量为100μL,质谱采用碰撞池模式进行测定。结果本方法在15 min内可以完全分离5种硒形态,硒代胱氨酸(Se Cys2)、甲基硒代半胱氨酸(Me Se Cys)、亚硒酸根(Se(Ⅳ))、硒代蛋氨酸(Se Met)、硒酸根(Se(Ⅵ))的检出限分别为0.6、0.7、1、0.9、1μg/L,样品加标回收率范围为82.1%~98.3%,相对标准偏差为1.6%~3.8%。结论本方法可以简单、快速、准确地测定富硒苹果中硒的5种形态。     

硒精氨酸对D-半乳糖诱导脑损伤小鼠的防护作用

目的:研究硒精氨酸(selenoarginine,SeArg)对D-半乳糖(D-gal)所致脑损伤的防护作用.方法:将40只昆明种小鼠随机分成4组:正常组、模型组、低硒剂量组、高硒剂量组.通过后颈背部皮下注射D-半乳糖建立脑损伤模型,以灌胃方式加入SeArg,连续处理6周,采用原子荧光法检测各组小鼠脑Se和血清Se含量,生化分析法检测脑组织匀浆GSH-Px、GSH、SOD、MDA、NO、NOS和血清NO与NOS水平,流式细胞仪检测脑细胞凋亡率,同时对脑组织切片做HE染色及Nissl染色,光镜下观察脑组织病理学变化.结果:与模型组相比,SeArg组小鼠Se、GSH含量和GSH-Px、SOD活性明显上调,MDA、NO含量以及NOS活性显著降低,脑细胞凋亡率明显下调.脑组织染色结果与生化检测结果一致.其中,低剂量的SeArg作用效果更佳.结论:SeArg对D-半乳糖所致的小鼠脑损伤有明显的防护作用,这种保护效应与SeArg能够清除自由基,提高抗氧化酶活性,增强抗氧化防御机制有关.     

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.