Occurrence of phenolic compounds in the seed coat and the cotyledon of peas (Pisum sativum L.)

This work determined the phenolic composition of the seed coat and the cotyledon of two varieties of dark peas (Pisum sativum L), Fidelia and ZP-840, by HPLC-PAD and HPLC-MS. High concentrations of glycosides of quercetin, luteolin and apigenin were found in the seed coat of both varieties of peas. Minor concentrations of monomers and dimers of proanthocyanidins were identified. The cotyledon mainly contains hydroxybenzoic and hydroxycinnamic compounds and some of the flavone and flavonol glycosides found in the seed coat. Two conjugated compounds with malic acid, trans p-coumaroyl-malic acid and p-hydroxybenzoyl-malic acid were identified in the cotyledon and in the seed coat, and the stilbene trans-resveratrol-3-glucoside, only in the seed coat. These compounds had not been previously reported in peas. The results obtained allow an overview of the distribution of the phenolic compounds in the seeds of these varieties of peas, and contribute to the knowledge of the implications of these compounds in the dietary intake.     

固相萃取-高效液相色谱法同时测定葡萄酒中没食子酸等8种多酚类化合物

建立了固相萃取.高效液相色谱光电二极管阵列检测法测定葡萄酒中没食子酸等8种多酚类生物活性化合物的方法.并用此方法测定了市售的7种葡萄酒中该8种生物活性物质的含量.实验确定了葡萄酒样品中的没食子酸等物质的固相萃取方法,通过优化萃取条件,有效的去除了葡萄酒中大量干扰成分.采用HypersilC18柱(250mm×4.6mm,i.d.5μm)分离.以乙腈-0.3%乙酸为流动相,线性梯度洗脱,以保留时间和特征光谱对分离出的组分予以定性确证,用峰面积进行定量.8种组分的质量浓度与其峰面积在一定的范围内有良好的线性关系,相关系数为0.9982～0.9999,8种组分的平均回收率为83.9%～103.7%(相对标准偏差为1.6%～4.6%),检测限为0.2～1.5mg/L.对市售的7种葡萄酒的检测结果表明,多酚类物质作为葡萄酒中重要的生物活性成分,其含量与葡萄酒的酿造方式,葡萄品种,葡萄产地有密切的关系.该方法简便、快速、灵敏,也适用于其它复杂体系中没食子酸等8种生物活性的成分分析.     

HPLC-PAD外标法及UPLC-MS/MS内标法测定乳及乳制品中三聚氰胺的含量

分别建立高效液相色谱-二极管阵列法(HPLC-PAD)、超高压液相色谱-串联质谱法(UPLC-MS/MS)测定乳及乳制品中三聚氰胺含量的方法。利用HPLC-PAD外标法进行样品中三聚氰胺的初筛,利用UPLC-MS/MS法进行确证,以13C315N3-三聚氰胺为同位素内标定量。乳制品经乙腈、乙酸锌、盐酸溶液提取,质谱检测时,样品再经MCX固相萃取柱富集净化。HPLC-PAD法的定量限为4mg/kg,UPLC-MS/MS的定量限为0.05mg/kg;HPLC-PAD的添加回收率为95.7%～102.3%,UPLC-MS/MS的添加回收率为91.3%～95.7%(基质匹配曲线校正),两种方法的相对标准偏差(RSD)分别为1.98%～4.51%,1.60%～3.27%。     

Antioxidant compounds and antioxidant capacity of Peruvian camu camu (Myrciaria dubia (H.B.K.) McVaugh) fruit at different maturity stages

The antioxidant capacities of ascorbic acid and phenolic compounds present in camu camu fruit were screened during ripening. Ascorbic acid decreased, and anthocyanin, flavonol and flavanol contents, and DPPH antioxidant capacity increased during ripening. Antioxidant compounds from camu camu were fractionated in two fractions: an ascorbic acid-rich fraction (F-I) and a phenolics-rich fraction (F-II). F-I was the major contributor to the DPPH antioxidant capacity (67.5–79.3%) and F-II played a minor role (20.7–32.5%). A total of 30 different phenolic compounds were detected by HPLC-PAD. The presence of catechin, delphinidin 3-glucoside, cyanidin 3-glucoside, ellagic acid and rutin was elucidated. Other phenolic compounds, such as flavan-3-ol, flavonol, flavanone and ellagic acid derivatives, were also present. For the three ripening stages the flavan-3-ols and ellagic acid group were the most representative phenolic compounds in this fruit. Acid hydrolysis of F-II revealed the presence mainly of gallic and ellagic acids, suggesting that camu camu fruit possesses important quantities of hydrolysed tannins (gallo- and/or ellagitannins). These results confirm that camu camu fruit is a promising source of antioxidant phenolics.