Cantos Emma, Espín Juan Carlos, López-Bote Clemente, de la Hoz Lorenzo, Ordóñez Juan A, Tomás-Barberán Francisco A
Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, P.O. Box 164, Murcia 30100, Spain.
J Agric Food Chem. 2003 Oct 8;51(21):6248-55. doi: 10.1021/jf030216v.
The aim of the present work was to identify and quantify the phenolic compounds and fatty acids in acorns from Quercus ilex, Quercus rotundifolia, and Quercus suber. The concentration of oleic acid was >63% of total fatty acids in all cases, followed by palmitic and linoleic acids at similar concentrations (12-20%). The concentrations of alpha-tocopherol in Q. rotundifolia, Q. ilex, and Q. suber were 19, 31, and 38 mg/kg of dry matter (DM), respectively, whereas the concentrations of gamma-tocopherol were 113, 66, and 74 mg/kg of DM, respectively. Thirty-two different phenolic compounds were distinguished. All of them were gallic acid derivatives, in the form of either galloyl esters of glucose, combinations of galloyl and hexahydroxydiphenoyl esters of glucose, tergallic O- or C-glucosides, or ellagic acid derivatives. Several tergallic acid C-glucosides were also present in the extracts obtained from Q. suber. Acorns from Q. ilex and Q. rotundifolia showed similar polyphenol patterns mainly with gallic acid-like spectra. Chromatograms of Q. suber showed mainly polyphenols with ellagic acid-like spectra. Valoneic acid dilactone was especially abundant in Q. suber skin. The contribution of skin to the total phenolics of the acorn was relatively small in Q. rotundifolia and Q. ilex but relatively high in Q. suber. Skin extracts from Q. suber, Q. rotundifolia, and Q. ilex showed 1.3, 1.4, and 1.0 antioxidant efficiencies, respectively (compared to that of butylhydroxyanisole). Endosperm extracts showed lower capacity to prevent lipid peroxidation than skin extracts.
本研究的目的是鉴定和定量冬青栎、圆齿栎和栓皮栎橡子中的酚类化合物和脂肪酸。在所有情况下，油酸浓度均占总脂肪酸的63%以上，其次是棕榈酸和亚油酸，浓度相似（12-20%）。圆齿栎、冬青栎和栓皮栎中α-生育酚的浓度分别为19、31和38毫克/千克干物质（DM），而γ-生育酚的浓度分别为113、66和74毫克/千克DM。共区分出32种不同的酚类化合物。它们均为没食子酸衍生物，形式为葡萄糖的没食子酰酯、葡萄糖的没食子酰和六羟基二苯甲酰酯的组合、没食子酸O-或C-糖苷，或鞣花酸衍生物。栓皮栎提取物中还存在几种没食子酸C-糖苷。冬青栎和圆齿栎的橡子表现出相似的多酚模式，主要具有类似没食子酸的光谱。栓皮栎的色谱图主要显示具有类似鞣花酸光谱的多酚。橡碗酸双内酯在栓皮栎树皮中特别丰富。在圆齿栎和冬青栎中，树皮对橡子总酚的贡献相对较小，但在栓皮栎中相对较高。栓皮栎、圆齿栎和冬青栎的树皮提取物的抗氧化效率分别为1.3、1.4和1.0（与丁基羟基茴香醚相比）。胚乳提取物防止脂质过氧化的能力低于树皮提取物。
