Biochemistry Department, Federal University of Technology, P.M.B. 704 Akure, Nigeria.
J Food Sci Technol. 2012 Dec;49(6):729-36. doi: 10.1007/s13197-010-0222-y. Epub 2011 Jan 22.
This study sought to determine the distribution of free and bound phenolics in some Nigerian citrus peels [orange (Citrus sinensis), grapefruit (Citrus paradisii) and shaddock (Citrus maxima)] and characterize the antioxidant properties. The free phenolics were extracted with 80% acetone, while the bound phenolics were extracted from the alkaline and acid hydrolyzed residue with ethyl acetate. Free phenolic extracts had significantly higher (P < 0.05) DPPH* scavenging ability than the bound phenolic extracts, except in orange peels where the bound phenolic extracts had significantly higher (P < 0.05) DPPH* scavenging ability. Bound phenolics from orange peels had the highest ABTS* scavenging ability (6.09 mmol./TEAC g) and ferric reducing antioxidant properties (FRAP) (71.99 mg/GAE 100 g), while bound phenolics from shaddock peels had the least ABTS* scavenging ability (1.35 mmol./TEAC g) and FRAP (2.58 mg/GAE 100 g) . Bound phenolics from grapefruit peels had the highest OH* scavenging ability (EC50 = 3.8 mg/ml), while bound phenolics from shaddock peels had the least (EC50 = 16.1 mg/ml). The phenolics chelated Fe(2+) and inhibited malondialdehyde production in rat's pancreas in a dose-dependent manner. The additive and/or synergistic action of the free and bound phenolics could have contributed to the observed medicinal properties of the peels; therefore, the high antioxidant properties of the free and bound phenolic extracts from orange peels could be harness in the formulation of nutraceuticals and food preservatives.
本研究旨在确定一些尼日利亚柑橘皮(橙子[Citrus sinensis]、葡萄柚[Citrus paradisii]和柚子[Citrus maxima])中游离和结合酚类物质的分布,并表征其抗氧化特性。游离酚类物质用 80%丙酮提取,而结合酚类物质则从碱性和酸性水解残渣中用乙酸乙酯提取。游离酚类提取物的 DPPH清除能力显著高于(P<0.05)结合酚类提取物,除了在橙皮中,结合酚类提取物的 DPPH清除能力显著较高(P<0.05)。橙皮中的结合酚类物质具有最高的 ABTS清除能力(6.09 mmol/TEAC g)和铁还原抗氧化能力(FRAP)(71.99 mg/GAE 100 g),而柚子皮中的结合酚类物质具有最低的 ABTS清除能力(1.35 mmol/TEAC g)和 FRAP(2.58 mg/GAE 100 g)。葡萄柚皮中的结合酚类物质具有最高的 OH清除能力(EC50=3.8 mg/ml),而柚子皮中的结合酚类物质具有最低的 OH清除能力(EC50=16.1 mg/ml)。酚类物质以剂量依赖的方式螯合 Fe(2+)并抑制大鼠胰腺中丙二醛的产生。游离和结合酚类物质的相加和/或协同作用可能导致了果皮观察到的药用特性;因此,橙皮中游离和结合酚类提取物的高抗氧化特性可以用于营养保健品和食品防腐剂的配方中。