Quantification Of Proanthocyanidins Research Articles

Quantification of cranberry proanthocyanidins by normal-phase high-performance liquid chromatography using relative response factors.

American cranberries (Vaccinium macrocarpon) contain primarily A-type proanthocyanidins (PACs), which have been shown to prevent urinary tract infection. Currently, the accurate quantification of cranberry PACs is still lacking. A normal-phase high-performance liquid chromatography (NP-HPLC) method using relative response factors was developed and validated to quantify cranberry PAC oligomers and polymers. PAC oligomers with degree of polymerisation (DP) 3-9 and total polymers were isolated from the cranberry juice concentrate. Characterisation of the isolated PAC oligomers was performed by ultra-performance liquid chromatography-high resolution mass spectrometry. The relative response factors of oligomers from DP 2-9 and total polymers were determined against procyanidin A2. Method validation was conducted to assess limit of detection, limit of quantification, the linearity and working range, precision and accuracy. In addition, quantifications of PACs by NP-HPLC using relative response factors and two other commonly used methods were conducted in three cranberry food products. Cranberries PACs oligomers contained both A-type and B-type linkage, with epicatechin and epigallocatechin as basic units. Method validation results suggested this method is reliable and reproducible. Quantifications of PACs by NP-HPLC using relative response factors yielded higher values than that by the other two methods. A NP-HPLC method using the relative response factors was developed and validated. This method provides a more accurate approach in determining cranberry PACs. It can be used to quantify individual oligomers from DP 2-9, total polymers and total PACs in cranberries and cranberry products.

甘蓝型油菜种子抗营养物质的研究

甘蓝型油菜是重要的油料作物，不仅可生产食用油，而且其饼粕富含蛋白质，可作为动物饲料。油菜种子中因含有大量抗营养物质，如多酚化合物、木质素和纤维素等，其中多酚物质主要包括单宁、原花色素、类黄酮、羟基苯丙烯酸的衍生物和芥子油苷等，这些物质会严重影响菜籽油的品质和饲料的营养价值。本文主要介绍这些抗营养物质的种类、分离和测定方法，为油菜品质育种和改良提供参考。 Rapeseed (Brassica napus L.) is the second largest oil crop in the world. And rapeseed meal, the by-product after oil processing, has been considered as a good source for protein and animal forage, which makes rapeseed an useful economic crop. However, the utilization of rapeseed is still limited to the existance of abundant anti-nutritional factors including phenolic compounds, lignin and fibre. Hence, improving the quality of rapeseed with reduced anti-nutritional factors is becoming the primary mission for rapeseed breeders. The phenolic compounds of rapeseed mainly include plant tannins, proanthocyanidins, flavonoids, hydroxycinnamic acid derivatives and glucosinolate. Since proanthocyanidins (PAs) is relevant to the formation of pigments in seed coat, many studies focused on discovering biosynthetic pathway and better quantification of PAs. At the same time, the group of anti-nutritional factors is interrelated to one another, which need to be deeply clarified by further studies in the future, including their synthetic precursors, biosynthetic pathway and molecular mechanisms.

Improved procedure to determine non-extractable polymeric proanthocyanidins in plant foods

Proanthocyanidins (PA) or condensed tannins, a major group of oligomeric and polymeric dietary polyphenols, have an essential role on the organoleptic and health-related properties of plant foods. Their content is usually determined by HPLC analysis of aqueous–organic extracts. However, appreciable amounts of polymeric PA that remain in the residues of extraction usually are not considered for the analysis. A complete quantification of PA requires an additional determination of these non-extractable PA (NEPA). The objective of this work was to develop a new procedure to determine the content of NEPA, based in depolymerization by butanolysis, which yields anthocyanidin monomers and xanthylium compounds. Samples and standard are treated with butanol/HCl with FeCl3 (100°C, 60 min), and absorbances at 555 nm (anthocyanidins) and 450 nm (xanthylium compounds) are measured in the hydrolysates. NEPA content determined in some plant foods suggests that procedures based just on anthocyanidin concentration overestimate the actual content.