植烟土壤适宜施硒量研究

采用大田试验方式,在硒含量较低的土壤上施用亚硒酸钠,分析其对烤后烟叶硒含量、品质及卷烟产品安全性的影响,确定了植烟土壤适宜施硒量。结果表明：（1）烤后烟叶硒含量随土壤施硒量增加呈现抛物线趋势,当土壤施用亚硒酸钠量为13.50 kg/hm²时,烟叶硒含量最高。（2）土壤施用亚硒酸钠为6.75~11.25 kg/hm²时,烟叶烟碱等化学成分含量较适宜、可用性较高,评吸质量较好。（3）富硒烟叶可降低卷烟产品细胞急性毒性、致突变能力以及诱导细胞活性氧产生的能力。通过综合分析土壤施硒量对以上各种指标的影响,确定植烟土壤施用亚硒酸钠的适宜量为6.75~11.25 kg/hm²。     

低硒土壤条件下施硒对烤烟烟叶品质的影响

通过田间试验,设置了土壤施硒(施硒量分别为30、40、50g/666.7m2)、叶面喷硒(喷硒量分别为500、1000μg/株)和不施硒共6个处理,研究了不同施硒方法对烤烟中部叶品质的影响。结果表明,随施硒量的增加,烤烟中部叶的还原糖和总糖含量降低,蛋白质、烟碱、总氮和钾含量升高,氯含量变化很小;施硒对中部叶的评吸质量无明显影响;施硒能明显降低烟气中的总粒相物和焦油含量,提高烟叶安全性。     

赣南富硒脐橙中糖度、酸度和维生素C含量的测定分析

以美国纽荷尔脐橙为供试品种,采用土施和喷施亚硒酸钠的脐橙富硒试验,系统测定分析了施硒量对富硒脐橙的糖度、有机酸酸度和维生素C含量的影响.结果表明:在施硒量为45～360mg/棵范围时,富硒脐橙中还原糖、转化糖、蔗糖、总糖的含量与施硒量是正相关,提高的最大幅度分别达到36.3％、30.2％、28.5％、20.9％;而富硒脐橙中有机酸含量与施硒量总体呈负相关,当施硒量在90mg/棵时,脐橙中有机酸含量下降最大,有机酸含量为0.85g/100mL果汁(以柠檬酸计),下降幅度达49.4％;在施硒量为45～90mg/棵范围时,维生素C含量与施硒量呈负相关,施硒量在180～360mg/棵范围时,外源硒对脐橙中维生素C的合成有促进作用.施用硒肥改善了脐橙的口感,提高了脐橙的品质.     

苦荞籽粒蛋白质营养评价及其对硒的响应

采用盆栽实验研究苦荞籽粒蛋白质营养评价对硒的响应。结果表明,不施硒时,苦荞籽粒必需氨基酸与氨基酸总量比值(E/T)和必需氨基酸与非必需氨基酸比值(E/N)分别为34.4% 和52.2%,与WHO/FAO 提出的E/T 约40%,E/N 约60% 相接近,苦荞蛋白质为优质蛋白。在所测定的必需氨基酸中,含硫氨基酸(蛋氨酸+ 胱氨酸)含量和各评分值均最低,是第一限制性氨基酸。除施硒量0.5mg/kg 土壤处理外,施硒使苏氨酸和赖氨酸含量有不同程度升高,蛋氨酸+ 胱氨酸随外源硒质量分数的增加而降低;施硒量≥ 1.0mg/kg 时,苦荞籽粒的粗蛋白(CP)、必需氨基酸、非必需氨基酸和氨基酸总量随施硒量的增加而增加;施硒量1.5～2.0mg/kg 土壤时,除含硫氨基酸(蛋氨酸+ 胱氨酸)外其余各必需氨基酸的含量和各评价指标均优于不施硒的处理。     

土壤和叶面施硒对烤烟硒积累的影响

通过盆栽试验,研究了不同来源硒对烤烟各器官硒含量和烟叶硒积累动态的影响。结果表明,不同施硒处理,烟叶硒积累速率均为单峰曲线,峰值在移栽后65 d左右,叶面喷硒处理峰值更高但下降也更迅速。烤烟各器官硒含量均随施硒量增加而增加。不同施硒方法对烟叶各叶位硒含量影响不同,土壤施硒处理不同叶位硒含量大小为上部叶>中部叶>下部叶,而叶面喷硒处理则为下部叶>中部叶>上部叶。     

施硒对大豆中辅酶Q_(10)含量的影响

为研究植物体内硒含量对辅酶Q含量的影响,以大豆为载体,通过叶面喷施亚硒酸钠进行富硒处理。采用原子荧光法测定大豆中硒含量,高效液相色谱法测定辅酶Q含量。考察了不同施硒浓度下大豆籽粒中硒和辅酶Q10含量。结果表明:随着施硒浓度的增加,大豆籽粒中硒累积量增加。硒含量由对照的78.89μg/kg,显著增加到345.12μg/kg;同时富硒大豆中籽粒中辅酶Q10含量也显著提高,且与硒含量呈线性关系,在研究的施硒浓度范围内,其线性方程为y=0.050 4x+2.374 8。与对照相比,施硒处理可以显著增加大豆籽粒中辅酶Q10含量,进而增加大豆的营养。     

枣中微量硒的原子荧光光谱法分析

采用原子荧光光谱法对枣中硒的含量进行分析,确定最佳测定条件。结果表明：硒的检出限为0.57ng/ml,线性范围为1.0～32.0ng/ml,回收率为99.0%～106.3%,变异系数小于1.71%。     

硒元素在绿豆芽中的富集研究

本研究根据绿豆芽的生长特点,设计出绿豆的发芽环境,同时选择不同浓度的硒溶液进行富硒试验,实验结果表明硒溶液浓度越大,豆芽生长速度就越慢,当浓度高于35ng/ml时,豆芽出现腐烂现象,而采用浓度低于20ng/ml的硒溶液淋浇时,对豆芽生长影响差异不明显。硒含量检测结果表明,与对照相比,富硒处理后的豆芽都达到了一定的富硒量。用浓度分别为20、35、50ng/ml硒溶液处理后的豆芽硒含量分别为27.03、100.7、155.6mg/kg。本实验还对不同富硒量对豆芽中SOD酶活性的影响进行了研究,结果表明豆芽的SOD酶活性先是随着硒溶液浓度的增大而增大,但硒浓度超过20ng/ml时又呈下降趋势,这说明过量的硒会抑制SOD酶活性。     

土壤施硒对烤烟光合特性及其同化物积累的影响

采用盆栽试验调查了不同硒浓度(0、1、2.5、5、10、15 mg/kg)施入土壤后,烤烟光合特性及其同化物积累的变化情况。结果表明,适量硒浓度可以降低烤烟叶片净光合速率(Pn)和叶绿素含量的下降率,延缓光合功能的衰退,同时延长光合同化产物的积累时间;过量硒浓度会提高Pn和叶绿素含量的下降率,加速光合功能的衰退,缩短光合同化产物的积累时间。土壤施硒对烤烟叶片光合功能及其同化产物积累的影响主要发生在烟株成熟期(移栽60 d以后),且随着叶片生育进程的推进,影响的程度越大。在烟株生育前期,施硒提高叶片Pn的原因可能是减少了气孔限制,而在生育后期,过量硒浓度引起Pn下降的主要因素是非气孔限制,叶绿素含量下降可能是一个重要原因。在本试验条件下,适宜的土壤施硒浓度为2.5和5 mg/kg。     

土壤施硒对白肋烟含硒量的影响

盆栽试验结果表明,在本试验设定的土壤施硒范围内,白肋烟叶、根、茎的含硒量分别为3.8~210、2.2~57、1.4~42μg/g,呈叶 > 根 > 茎的分布规律,而且均与土壤施硒量呈极显著的正相关;白肋烟叶、茎、根的吸硒量分别为0.208~11.343、0.143~3.682、0.032~1.000 mg/pot,呈现叶 > 茎 > 根的分布规律,亦均与土壤施硒量呈极显著的正相关:叶、茎、根的吸硒量占烟株总吸硒量的比例分别为54.3%~70.8%、20.8%~37.5%、5.5%~9.5%,说明白肋烟的硒积累能力为叶 > 茎 > 根;白肋烟对土壤施硒的回收率为8.9%~18.1%。      

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。     

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.     

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。     

Selenium and Chromium Content of European Beers as Determined by AAS

The chromium and selenium content of 74 domestic and imported brands of beer were determined by atomic absorption spectrometry to evaluate the importance of beer as a dietary source of both elements. Chromium content of the selected beers ranged from less than 0.2 to 46 ng/ml, whereas selenium content varied from 0.2 to 15.2 ng/ml. The concentration levels were compared to literature data and the contribution of beer to the daily intake of both elements in Belgium was calculated. Chromium accounted for 5%, while selenium contribution was less than 1%. No definite correlation was found between chromium and selenium concentration and type of fermentation; also, chromium content was not related to selenium level.     

豌豆粉丝中硒含量的测定

以HNO3和H2O2溶解样品,建立了顺序注射氢化物发生-原子荧光法测定豌豆粉丝中硒的分析方法。研究了仪器条件、实验条件、微波消解方式、预还原剂等因素对硒测定的影响,探讨了共存离子的干扰及消除,确定了最佳工作条件。结果表明:方法的最低检出限为0.10ng/ml,线性范围0～80ng/ml。应用该方法测定了不同的豌豆粉丝,相对标准偏差为2.94%～4.01%,加标回收率为90.33%～102.31%。     

An LC-MS/MS-SRM Method for Simultaneous Quantification of Four Representative Organosulfur Compounds in Garlic Products

The quantitative analysis of organosulfur compounds is important for the quality control of various garlic products along with studying their molecular functionality and nutraceutical properties. In this study, a liquid chromatography-tandem mass spectrometry-selected reaction monitoring (LC-MS/MS-SRM) method with electrospray ionization detection was developed and validated for the rapid, simultaneous quantification of four representative organosulfur compounds in garlic: alliin, S-allyl-L-cysteine, γ-glutamyl-S-allyl-L-cysteine, and allicin. Stable SRM transitions were achieved for these compounds under optimized conditions, and the linear range extended from 1 to 2000 ng/mL. The limits of detection and quantification ranged from 0.003 to 0.058 ng/mL and from 0.01 to 0.19 ng/mL, respectively. Excellent recovery and reproducibility at different spiking levels were achieved. The method was successfully applied to the simultaneous quantification of organosulfur compounds in fresh garlic samples. This highly selective and sensitive LC-MS/MS-SRM method is expected to be a useful tool for studying molecular functionality and the quality control of garlic products.     

微波消解-石墨炉原子吸收光谱法检测大米中硒元素的含量

为了建立一种微波消解-石墨炉原子吸收光谱法测定大米中硒含量的方法,以微波消解为前处理,并以1mg/mL的硝酸镁为改进剂,采用石墨炉原子吸收光谱法进行硒的测定。此方法的标准曲线的回归方程为:Y=0.0378X-0.0051,R=0.9983,线性范围为2.5-15ng/mL,检出限为1ng/mL,精密度(RSD)为1.64%,重现性(RSD)为3.59%。样品的加标回收率在92.0%-101.0%。     

Glutathione peroxidase activity, and content of total and soluble selenium in five bovine and porcine organs used in meat production

Glutathione peroxidase (GSHPx) activity, and total and soluble selenium content were compared in five bovine and porcine organs. The highest GSHPx activity in porcine tissues was found in the liver (35.0 U/g), spleen (29.3 U/g) and kidney (27.3 U/g) with much lower values in the heart (1.8 U/g) and diaphragm (0.8 U/g). A different pattern with lower inter-organ variation in GSHPx activity was observed in cattle: kidney (8.5 U/g), spleen (8.0 U/g), heart (5.8 U/g), liver (4.0 U/g) and diaphragm (2.1 U/g). The total selenium content was similar in both species with the highest content in the kidney (1764 and 1665 ng/g; pig/bovine), followed by liver (533 and 307 ng/g), spleen (370 and 284 ng/g), heart (201 and 205 ng/g) and diaphragm (144 and 116 ng/g). The percentage of soluble selenium varied more among the pig organs (46–94%) than among bovine organs (61–75%). The results show a marked variation in the activity of the selenium-containing GSHPx among organs and species in spite of a similar rank order of selenium content in the two species. Since GSHPx has a role in food stability and the intake of selenium is marginal in many European countries, the results add to the background information concerning the use of selenium rich organs as human foods.