山东苍山县大蒜中硒含量测定

采用荧光分光光度法分别对山东省苍山县和济南产吕蒜中硒含量进行了山县大蒜中硒含量明显高于济南产大蒜。苍山居居民素有种蒜、食蒜习惯,因此长期良含硒高的大蒜可能与此地区胃癌发病率低有一定关系。     

氢化物原子荧光法测定大蒜及其制品中的硒

目的：测定大蒜及其制品中硒的含量。方法：大蒜、蒜氨酸、蒜酶、大蒜多糖样品经过HNO3-HClO4湿法消解,采用氢化物原子荧光光谱法测定硒的含量。结果：大蒜、蒜氨酸、蒜酶、大蒜多糖中硒的含量分别为0.010～0.024、0.423～0.629、0.057～0.064、0.001～0.007μg/g。结论：该方法测定大蒜及其制品中硒的含量,操作简便,灵敏度高。     

醋蒜中抗氧化成分的研究

采用3种类型的大蒜制备醋蒜,并对鲜蒜、原醋和3种醋蒜中的抗氧化成分大蒜素、硒、铁、锰、维生素C、维生素E和氨基酸进行分析.结果表明:与鲜蒜相比,3种醋蒜中铁、锰和部分氨基酸的含量有所增加;大蒜素、硒、维生素E和部分氨基酸含量略有降低,维生素C损失较大;采用完整大蒜制备的醋蒜中抗氧化成分损失率最小;浸泡28 d后,醋蒜中抗氧化成分含量趋于稳定.醋蒜这种大蒜加工方法,可以保存大蒜中大部分抗氧化成分.     

氢化物发生-原子荧光法测定大蒜中的硒

本文建立了氢化物发生-原子荧光光谱法(HGAFS)测定蒜硒的分析方法,方法线性范围是0～60ng/ml,r=0.9997,检出限为0.15ng/ml。将所建立方法用于考察不同施硒土壤中所生长大蒜的硒含量。结果表明:蒜能够富集土壤中的硒,且蒜硒含量与土壤中施硒溶液中硒的含量呈正相关。     

大蒜与胃癌 大蒜对胃内亚硝酸盐及硝酸盐的影响

苍山县胃癌死亡率（3．43/10万）是山东省最低的县,只有死亡率（40．08/10万）最高的栖霞县的1/12。苍山县以种植大蒜著称,当地居民常年以生大蒜佐餐（例如神山公社每人每日平均食用大蒜20克）,其胃癌死亡率低是否与这一饮食习惯有关值得研究。为此我们进行了高低死亡区栖霞县和苍山县部分居民胃内NO2-和NO3-的测定,以及食蒜前后胃内亚硝酸盐、硝酸盐含量的测定,并对栖霞县和苍山县居民部分外环境即水和粮     

浅谈大蒜系列产品的开发现状

大蒜古名葫,又名葫蒜、独蒜,为百合科葱属植物蒜(AlliumSativumL.)的鳞茎,是香辛类蔬菜之一。大蒜中的有效成分有大蒜辣素、大蒜新素及多种烯丙基硫醚化合物,总称为大蒜素或大蒜精油。它含有大量对人体有益的蛋白质、氨基酸、维生素、脂肪、糖类、尼克酸、核黄素、微量元素及硫化物等,尤以微量元素硒含量较高。1990年8月在美国召开的关于大蒜保健意义及其成分的首届会议证实了大蒜能在不同程度上防治结肠癌、膀胱癌、皮肤癌和肝癌。目前,大蒜制剂如大蒜注射液、大蒜素、大蒜新素等已用于医学临床中。因此大蒜系列产品开发前景将十分广阔。…     

三个不同省份富硒大蒜硒含量分析

目的:检测山东、黑龙江、江西三个省份富硒大蒜、普通大蒜、土壤及水源的硒含量,为当地富硒大蒜产业发展提供科学依据。方法:采集山东、黑龙江、江西三个省份富硒大蒜、普通大蒜、土壤及水源共120份,采用电感耦合等离子体质谱法测定总硒含量。结果:山东省富硒大蒜硒含量高于普通大蒜中硒的含量;黑龙江省来信子村富硒大蒜硒含量明显高于其他4个基地;江西省5个地区富硒大蒜硒的含量可以分为两个区间:硒含量较低的区间(11.660 0～31.984 0μg/100 g)、硒含量较高的区间(86.530 0～97.224 0μg/100 g)。结论:山东省的富硒大蒜富硒效果好,黑龙江省宝清县来信子村富硒大蒜的富硒效果好,江西省宜春县富硒大蒜均为超富硒农产品。     

不同烹饪方法对大蒜素影响的研究

在空白试验的基础上,利用定硫法测定经过不同烹饪方法加工后,大蒜中大蒜素的含量。结果如下：油炸大蒜后的大蒜辣素含量0.0677g/100g,蒸制大蒜后的大蒜辣素含量0.0684g/100g,水煮大蒜后的大蒜辣素含量0.0845g/100g,微波加热大蒜后的大蒜辣素含量0.1914g/100g。结论：破坏大蒜素最小的烹饪方法是微波加热法,破坏最大的是油炸烹调法。     

科学家发现喝牛奶可消除大蒜味

<正>美国一项研究发现,吃完大蒜或食用过程中喝牛奶有助于消除口气中令人不悦的蒜味。大蒜富含镁、硒、维生素B6和维生素C等成分,具有降低血压和胆固醇等功效,有益健康。但吃完大蒜后,那种挥之不去的"蒜香"往往招人厌恶。     

影响蒜素提取率的因素研究

大蒜中含有人体所必须的多种营养物质,其主要活性成分是大蒜辣素、蒜氨酸、大蒜新素等化合物,主要的风味成分是蒜辣素。为了避免食用调和蒜油产品中的有机溶剂残留和有效成分的损失,本研究直接采用一级菜籽油常温浸提蒜素等成分,由于大蒜中蒜辣素的含量高低及稳定性直接影响蒜油的质量。因此考察了大蒜与提取油质量比、提取时间和大蒜破碎度等因素对蒜素含量及提取工艺的影响,结果表明当蒜油质量比为1.2∶1,浸提时间12 h,大蒜打浆时间为1.5 min时,蒜辣素含量最高,达到0.2813 g/dL。     

大蒜的生物富硒作用及其硒的形态分析

通过大蒜叶面喷施硒肥的田间试验,分析大蒜头和大蒜茎叶中硒含量,采用水提、酸提和酶提3种方法提取大蒜中的硒的形态,利用高效液相色谱联用电感耦合等离子体质谱仪(HPLC-ICP/MS)方法测定普通大蒜和富硒大蒜中的硒形态。结果表明：通过叶面喷施硒肥,大蒜蒜头硒含量从0.047μg/g显著提高到0.200～0.834μg/g (P＜0.05),大蒜茎叶硒含量从0.043μg/g显著提高到0.291～0.962μg/g(P＜0.05)。通过比较的3种硒形态提取方法,证明酶法提取率最高,为较优方法。普通大蒜和富硒大蒜中的主要硒形态为MeSeCys、SeCys2和SeⅣ。与普通大蒜相比,通过叶面喷施硒肥后,大蒜头中主要转化的有机硒形态为MeSeCys,占总提取硒的81.2%,并进一步通过电喷雾质谱(ESI-MS)鉴定MeSeCys的结构,但酸提液中仍存在未知硒峰,需进一步鉴定。     

氢化物发生-原子荧光光谱法测定大蒜中的硒含量

目的:建立检测大蒜中硒含量的方法。方法:采用正交试验设计对仪器条件进行优化,采用单因素试验分析探讨最佳氢化反应条件,通过湿法消化(混酸:硝酸∶高氯酸为9∶1)预处理大蒜,用氢化物发生-原子荧光光谱法测定。结果:该方法线性范围为1~20μg/L,线性相关系数r为0.9998,检出限为0.06μg/L,加标回收率为91.5%~102.8%,精密度为3.1%(n=6),3种大蒜中硒的含量分别为5.80,4.36,3.90μg/100g。结论:该方法线性良好,灵敏度和准确度高,精密度好,适用于大蒜中硒含量的测定。     

苍山大蒜低聚糖纯化技术及分子质量测定

文中研究了苍山大蒜中低聚糖(GOS,garlic oligosaccharide)的分离纯化技术,并测定其分子质量。分别研究了聚酰胺柱色谱法对蛋白质的脱除效果;离子交换色谱法,有机溶剂沉淀法和葡聚糖凝胶色谱法对GOS的纯化效果。结果表明:聚酰胺色谱柱对大蒜粗糖中蛋白质有良好的脱除效果,糖回收率为98.9%,蛋白质脱除率为66.8%;DEAE-纤维素(OH~-)色谱柱可将大蒜低聚糖分为3个组分;乙醇分级沉淀可将大蒜低聚糖分为8个组分;Sephadex G-25纯化后的GOS的HPLC测定结果表明,其纯度为99.1%,Mw/Mn=1.31,数均分子质量为1770u。     

Determination of selenium in garlic by cathodic stripping voltammetry

The selenium content in a garlic sample was determined on hanging mercury drop electrode (HMDE) using cathodic stripping voltammetry (CSV). In this method the dried garlic sample was digested in HNO₃:HClO₄ (1:1) by wet-digestion procedure. The CSV voltammogram in 0.1 M HCl solution showed a peak for Se at −0.56 V. Effect of deposition potential, deposition time and sweep rate on this peak were tried to determine the optimum experimental conditions. A deposition potential of −0.2 V was applied for 120 s while stirring the solution by passing nitrogen and followed a potential scan of 50 mV/s in a negative direction. The standard addition method was used to determine selenium in the sample. The linear domain range of Se (IV) was 2.0×10⁻⁸–6.0×10⁻⁷ M with a correlation coefficient of 0.9985. This method was used for the first time for the determination of selenium in garlic sample without any separation procedure and preconcentration techniques such as ion exchange, solvent extraction or hydride generation. The amount of selenium determined in three different samples from three different regions were 370±26 (n=5), 485±35 (n=4) and 365±46 (n=4) ng/g (dry-weight) with relative standard deviations of 7.0, 7.2 and 12.6%, respectively.     

大蒜中微量硒的测定

文章以丁基罗丹明B作显色剂,吐温-80作表面活性剂,在pH4.0的邻苯二甲酸氢钾-盐酸缓冲溶液中,硒与硫氰酸盐及丁基罗丹明B形成稳定的三元络合物,该络合物的最大吸收波长为610 nm,其摩尔吸光系数ε610=2.8×105 L·mol-1·cm-1.硒含量在0～2.8 μg/25 mL范围内符合朗伯比耳定律,该方法用于大蒜中硒的测定,结果满意.     

Selenium speciation in enriched vegetables

The ability of several plants to accumulate and transform inorganic forms of selenium into bioactive organic compounds has important implications for human nutrition and health. Se-enriched Allium group vegetables such as garlic, onion and ramps have been mainly the subject of several studies in the recent years. Apart from the total Se uptake, enrichment treatments normally undergo certain metabolic changes that determine the final product as well as its translocation and accumulation in different plant tissues. For this reason, it is important to find which form of selenium should be used for supplementation to obtain a high content of this element in the final plant. Moreover, its distribution in different parts of plants as well as characterisation and quantification of individual species becomes an issue. This review gives a brief, critical overview of the studies carried out to characterise selenium species produced by different enriched vegetables. The use of different extraction and clean-up methodologies will be discussed in conjunction with different selenium enrichment procedures.     

Determination of selenium in garlic (Allium sativum) and onion (Allium cepa) by electro thermal atomic absorption spectrometry

A separation/enrichment procedure has been developed for the determination of selenium in garlic and onion samples by electrothermal atomic absorption spectrometry (ET-AAS) as a slurry sampling after preconcentration with 3,3-diaminobenzidine (DAB) reagent on the activated carbon. The influences of pH, time, amount of carbon and complexing reagent were outlined. The effect of acids used in the digestion of samples was also studied and compared. Selenium level was found to be 0.024 μg g⁻¹ for onion (n = 5; LOD – 0.5 μg L⁻¹; LOQ – 1.7 μg L⁻¹) and 0.015 μg g⁻¹ for garlic (n = 5; LOD – 1.3 μg L⁻¹; LOQ – 3.3 μg L⁻¹). Three different samples of garlic were analyzed by k₀-instrumental neutron activation analysis (k₀-INAA) at the Jozef Stefan Institute (JSI). The data obtained by k₀-INAA show that the content of selenium overlapped the results obtained by ET-AAS.     

双波长分光光度法测定大蒜中硒含量

在0.16mol/L硫酸中,硒(Ⅳ)与过量的碘化钾反应生成I3-,I3-进一步与番红花红T(ST)形成稳定的离子缔合物ST.I3,使ST褪色,405nm处出现正吸收峰,521nm处出现负吸收峰。选定测量波长为405nm,参比波长为521nm,建立了双波长分光光度法测定硒的新方法。硒(Ⅳ)浓度在0～0.6μg/mL范围内服从比尔定律,表观摩尔吸光系数ε为1.05×105 L/mol.cm,检出限为1.42μg/L。方法用于测定大蒜中硒,结果与荧光法一致。相对标准偏差0.6%～1.0%(n=5),平均回收率为97.4%～98.6%。