黑洋葱多酚成分提取及抗氧化研究

Study on Extraction and Antioxidation of Polyphenols from Black Onion

为了观察黑洋葱和紫皮洋葱的抗氧化作用,该实验以紫皮洋葱为原料,将其发酵成黑洋葱。将新鲜洋葱放置于恒温恒湿发酵箱中,经过一定温度调控后,发酵1个月后制成的一种黑洋葱食品。黑洋葱发酵过程中的紫皮洋葱颜色逐渐变黑,发生了美拉德反应。采用微波辅助提取法提取黑洋葱中多酚化合物,同时使用福林酚法测定黑洋葱和紫皮洋葱多酚含量并对二者进行比较,比较黑洋葱多酚成分和紫皮洋葱多酚成分的抗氧化性。结果表明:黑洋葱中多酚含量为25.76 mg/g,大于紫皮洋葱多酚含量。黑洋葱多酚的DPPH自由基清除率为94.16%,总还原能力为1.296,羟基自由基清除率为98.78%,均明显大于紫皮洋葱。

In order to observe the antioxidation effect of black onion and purple onion,purple onion is fermented into black onion.Black onion food is prepared by putting fresh onion in constant-temperature and constant-humidity fermentation tank and being fermented for one month after a certain temperature control.During the fermentation process of black onion,the color of purple onion turns black gradually,and Maillard reaction occurs.Microwave-assisted extraction method is used to extract polyphenols from black onion,and the content of polyphenols in black onion and purple onion is determined by Folin-phenol method.The antioxidant activities of polyphenols from black onion and purple onion are compared.The results show that the content of polyphenols in black onion is 25.76 mg/g,which is higher than that in purple onion.The DPPH radical scavenging rate,the total reducing capacity and the hydroxyl radical scavenging rate of black onion polyphenols is 94.16%,1.296,98.78%respectively,which are significantly higher than those of purple onion.