硬脂酰单宁酸酯的合成及抗氧化作用

Synthesis of Stearoyl Tannic Acid Ester and Its Antioxidant Effect

以单宁酸和硬脂酰氯为原料合成了一种油溶性抗氧化剂硬脂酰单宁酸酯 (C18 TA)。探讨了硬脂酰氯和单宁酸的量比、催化剂对甲苯磺酸的用量、反应温度和溶剂等对合成的影响。确定了较佳的反应条件 :n(单宁酸 )∶n(硬脂酰氯 ) =1∶2 0 ,m(单宁酸 )∶m(催化剂 ) =1 0 0 :0 .0 3 ,二氧六环作溶剂 ,反应温度 10 0～ 10 2℃ ,氮气保护下反应 4h。C18 TA在菜籽色拉油中的含量为6 0 0mg/kg时 ,6 0℃强制氧化 18d ,其POV抑制率可达 6 6 0 % ,明显高于相同条件下BHT的POV抑制率 5 6 0 %

Tannic acid (TA) is an excellent natural antioxidant, but its utilization in food and oil industries has been limited due to its poor lipophilicity. Therefore, the synthesis of oil-soluble tannic acid derivative, stearoyl tannic acid ester (C18-TA), was studied by using tannic acid and stearoyl chloride as reactants. The main factors affecting the reaction such as ratio of reactants, the catalyst (p-toluenesulfonic acid), temperature and solvent were discussed. The optimum reaction conditions were as follows. n(TA):n(stearoyl chloride) = 1:20, m(TA): m(catalyst) = 1.00:0.03. The reaction was conducted at reflux temperature of dioxane (100 - 102°C) for 4 h under the protection of nitrogen atmosphere. It was found that the peroxide - inhibiting rate of C18-TA (66%) was higher than that of BHT(56%) when both samples of colza oil with same concentration (600 mg/kg) of antioxidant were incubated at 60°C for 18 days.