Kernel vitreousness and protein content: Relationship,interaction and synergistic effects on durum wheat quality

Four sets of durum samples were used in this study to further understand the interrelationships among hard vitreous kernels (HVK), protein content, and pigment concentration, with a focus on the interaction and synergistic effects of protein content and vitreousness on durum quality. HVK level increases with higher protein content in the range of 9.5–12.5%, but this relationship is less evident in durum samples with high protein content (12.5–14.5%). Both protein content and kernel vitreousness can significantly affect durum milling quality. White starchy kernels (WSK) in low protein durum have a very detrimental impact on milling and pasta processing quality, but high protein content can mitigate the adverse impact of WSK on durum quality. Although protein content plays a dominant role, higher HVK might contribute positively to pasta firmness. There was no significant difference in yellow pigment content between HVK and WSK. However, pigment loss from semolina to dough was higher for WSK than HVK. Despite the difference in protein content, HVK and WSK have little difference in gluten strength. The monomeric protein was preferentially accumulated in HVK. The glutenin proteins of HVK and WSK were similar in the ratios of 1Bx/1By and HMW/LMW-GS.     

Preliminary study of patients with chronic mountain sickness by GC-TOF-MS based serum metabolomics analysis

AIM: To evaluate specific metabolomics profiles in the serum of patients with chronic mountain sickness (CMS) and to explore the potential metabolic biomarkers in the native Tibetans living on the Qinghai-Tibet Pla-teau.METHODS: A gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) approach as a metabolomics technique was used to evaluate metabolic differences. The native Tibetan CMS patients (n=10) and healthy Tibetan controls (n=10) were enrolled from YuShu in Qinghai province in this study. The serum samples were collected and analyzed by GC-TOF-MS coupled with a series of multivariate statistical analyses such as principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and orthogonal partial least squares discriminant analysis (OPLS-DA).RESULTS: The intergroup differences between CMS patients and control subjects have been observed. A list of differential metabolites and several top altered metabolic pathways have been identified. The levels of fumaric acid, an intermediate in the tricarboxylic acid (TCA) cycle, and inosine were highly upregulated in the CMS patients, suggesting a greater effort to hypoxic adaptation in high elevation area. Other differential metabolites, such as methyl phosphate, 2-ketoadipate, lyxose and phytanic acid were also identified. Importantly, the differential metabolites possessed higher area under the ROC curve (AUC) values, indicating an excellent clinical ability for the prediction of CMS. Increased levels of amino acids (isoleucine, glycine, serine, L-cysteine, citrulline and trimethyllysine) were detected in CMS group, yet significantly decreased levels of sulfuric acid, oxamic acid, lyxose and glutamine were also detected in CMS group than those in control group. At the same time, the levels of ribose and glucose-1-phosphate were markedly elevated in CMS group (P<0.05).CONCLUSION: The metabolic activities are significantly altered in the serum of CMS patients. High altitude hypoxia may act on the disturbed glucose metabolism and amino acid metabolism in part of the Tibetan triggered by CMS.     

离子色谱法同时测定降水中的常见阴离子

利用离子色谱仪同时测定降水中的3种有机酸根离子和4种无机阴离子,通过对分析条件的优化,确定了最佳的色谱条件：以4．0mmol／L Na2CO3与1．0mmol／L NaHCO3为流动相,流速0．8mL／min作等度洗脱,在10min内实现基线分离并完成电导检测．7种组分的检测限在0．5～20．0nmol／L之间,线性范围跨越2个数量级以上．该方法用于雨水样品的分析,结果表明：平均加标回收率为92．1％～106．2％,相对标准偏差0．30％～4．03％.     

鸡肉中三聚氰胺残留量检测方法研究

[目的]为检测动物性食品中的三聚氰胺提供参考方法。[方法]以鸡肉匀浆为材料,用高效液相色谱法和气相质谱法检测其中的三聚氰胺含量,并对检测方法的回收率和精密度进行测定。[结果]高效液相色谱法确定的鸡肉中三聚氰胺的最低检测限为1μg／g,最低定量限为2μg/g,在0．05-50μg范围内线性关系良好;方法的回收率大于80％,测定结果的日内变异系数小于7％,日间变异系数小于10％。气相质谱法确定的三聚氰胺的最低检测限为30ng／g,最低定量限为5030ng/g,在5—500ng／g范围内线性关系良好;方法的回收率在80％以上,测定结果的日内变异系数小于8％,日间变异系数小于10％。[结论]该研究为鸡肉中三聚氰胺的检测提供了新方法。     

小花棘豆内生真菌中苦马豆素的鉴定及含量测定

[目的]探索体外培养出的小花棘豆埃里砖格孢属内生真菌是否产生苦马豆素,进而深入研究植物的毒性与内生真菌的关系。[方法]用化学方法从培养的小花棘豆内生真菌菌丝体样品中提取苦马豆素,并对样品的分子离子结构进行质谱分析鉴定。[结果]样品中均含与标准品苦马豆素相同的质荷比m/z为174的特征峰,从而确定了样品中含苦马豆素;气相色谱法测定样品中苦马豆素的含量在24～100μg/g。[结论]该研究首次发现体外培养的小花棘豆埃里砖格孢属内生真菌能产生苦马豆素,认为植物的苦马豆素毒性应与该内生真菌有关。     

沙棘茶中脂肪酸的分析与测定

[目的]分析并测定沙棘茶中的脂肪酸。[方法]采用索氏提取法提取沙棘绿茶和沙棘红茶中的脂肪酸,并通过气质联用法对脂肪酸的化学组成及含量进行了测定分析。[结果]气质检测结果表明,2种沙棘荼的脂肪酸化学组成相同,均含有十四烷酸（肉豆蔻酸）、十五烷酸、十六烷酸（棕榈酸）、十八碳二烯酸（亚油酸）、十八碳烯酸（油酸）、十八碳三烯酸（亚麻酸）、十八烷酸（硬脂酸）、二十烷酸（花生酸）和二十烷烯酸等9种脂肪酸。[结论]该方法准确、简便,适用于沙棘茶中脂肪酸的分析和含量测定。     

铺地柏挥发性成分的GC-MS分析

[目的]对铺地柏挥发性成分进行分析。[方法]采用同时蒸馏萃取法提取,用气相色谱质谱联用（GC-MS）法结合计算机谱图检索,对铺地柏挥发性化学成分进行分析鉴定。[结果]铺地柏挥发油提取率为0.68%,共鉴定出88种化合物,占分离物质的85.74%。主要成分为β-水芹烯（17.06%）、（-）-4-萜品醇（2.96%）、β-香茅醇（2.34%）、2-十一烷酮（8.35%）、3,7-二甲基-6-辛烯酸甲酯（5.87%）和α-杜松醇（4.07%）。[结论]该研究通过对铺地柏挥发性成分的研究,为铺地柏资源的进一步开发利用提供了试验依据。     

糙米中丁硫克百威及其代谢物的残留测定

[目的]监测与评价糙米中丁硫克百威及其代谢物克百威、3-羟基克百威的残留量。[方法]建立凝胶渗透色谱（GPC）净化、气相色谱-质谱（GC-MS）同时测定糙米中丁硫克百威及其代谢物克百威、3-羟基克百威残留的方法。样品中的待测农药组分采用环己烷-乙酸乙酯（1∶1,V/V）提取,GPC和中性氧化铝（A l2O3）小柱净化,GC-MS测定。[结果]丁硫克百威和克百威的最低检测量均为2.0×10-11g,3-羟基克百威为1.0×10-10g;最低检出质量分数均为0.1 mg/kg,各组分的添加回收率为77.8%～94.6%,变异系数为3.86%～6.58%。[结论]凝胶渗透色谱净化-气相色谱质谱法测定丁硫克百威及其代谢物在糙米中的残留方法灵敏度、准确度、精密度均符合农药残留分析的要求,可用于检测糙米中丁硫克百威及其代谢物的残留量。     

苹果和土壤中三乙膦酸铝含量的气相色谱分析

[目的]研究三乙膦酸铝农药在苹果及土壤中的残留量,以促进安全生产。[方法]样品采用硫酸溶液提取,三甲基硅重氮甲烷正己烷溶液进行衍生,通过气相色谱-火焰光度检测器测定,面积外标法定量检测。[结果]方法检出限为9.5×10-3mg/kg,回收率为79.8%~117.1%,相对标准偏差为7.0%~12.3%。[结论]该方法简便、快速、准确度高、精密度好。     

气相色谱/质谱(GC/MS)测定蔬菜中甲基对硫磷农药和呋喃丹的优化

利用气相色谱/质谱(GC/MS)同时测定及确定蔬菜中甲基对硫磷农药和克百威(呋喃丹)的残留量。研究了振荡提取时间、提取剂用量、盐加入量、浓缩条件等操作条件对分析方法的影响。得到的优化分析条件如下:振荡提取时间为90 min、提取剂用量为70 mL、盐加入量为3 g、浓缩条件为温度50℃低压0.09 atm;该方法的相对标准偏差<10%,样品的加标回收率为甲基对硫磷82.5%、克百威为93.5%。本方法可以满足这2种杀虫剂在蔬菜中的检测要求。