Characterisation and free radical scavenging activities of novel red pigment from Osmanthus fragrans

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• 作者：Yingming Pan ; Zhiren Zhu ; Zhili Huang ; Hengshan Wang ; Ying Liang ; Kai Wang ; Qian Lei ; Min Liang
• 关键词：Osmanthus fragrans’ ; seeds ; Red pigment ; Physical and chemical properties ; Free radical scavenging activities
• 刊名：Food Chemistry
• 出版年：2009
• 出版时间：15 February 2009
• 年：2009
• 卷：112
• 期：4
• 页码：909-913
• 全文大小：229 K

文摘

A novel red pigment (RP) was isolated from Osmanthus fragrans’ seeds. The optimised experimental parameters of extraction obtained with a four-factor at three-level orthogonal array experimental design L₉(3⁴) were ethanol concentration, temperature, pH and extraction time as 90 % , 78 °C, 2.5 and 40 min, respectively. A yield of 34.6 ± 2.2 g/100 g was obtained under optimised conditions. The red pigment directly from O. fragrans’ seeds can be dissolved in alkaline, acidic waters solutions and hydrophilic organic solvents in common use. The colour of a water solution of RP changed with pH. RP was stable to heat in the temperature range of 25–100 °C. Physical and chemical properties of RP revealed that the red pigment was also stable in the presence of Na₂SO₃, NaCl, amino acid, organic acid, sugar, starch or metal-ions (such as Ca²⁺, Cu²⁺, Fe³⁺, Zn²⁺, Al³⁺, Mg²⁺ and Na⁺), but was bleached by strong oxidants (KMnO₄, K₂Cr₂O₇ and NaOCl). Subsequently, free radical scavenging activities of RP were assessed using 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals using a new resonance scattering spectral method. RP showed an excellent DPPH radical scavenging activity and was superior to butylated hydroxytoluene (BHT), and exhibited quite a strong concentration-dependent inhibition of hydroxyl radical at low concentrations compared with ascorbic acid and quercetin. When the concentration of RP was 0.03 μg/ml, the scavenging percentage of hydroxyl radical reached 92.3 % . Salidroside was isolated as an active principle.