紫娟茶花青素的抗氧化活性及稳定性

Antioxidant Activity and Stability of Anthocyanins from Zijuan Tea

目的:研究紫娟茶花青素的抗氧化活性及稳定性。方法:采用FRAP法、ABTS法和DPPH法测定紫娟茶花青素的抗氧化能力,并以紫娟茶花青素的保存率为考察指标,探讨贮藏条件对其稳定性的影响。结果:当紫娟茶花青素的FRAP值为0.5 mmol/L时,所需花青素浓度为0.39μg/m L;其清除ABTS^+·和DPPH·的IC_(50)分别为0.76和0.13μg/m L;在供试浓度范围内,紫娟茶花青素的总抗氧化能力、清除ABTS^+·和DPPH·能力均与其浓度呈正相关,且均强于V_C。p H可明显影响紫娟茶花青素溶液的颜色和光谱特性,当p H≤6.0时,其颜色变化相对稳定;随着温度升高、保存时间延长,紫娟茶花青素的保存率逐渐降低(p<0.05);光照、氧化剂(H_2O_2)、还原剂(Na_2SO_3)及金属离子(Fe^(3+)、Cu^(2+)、Mg^(2+)、Ca^(2+)、Al^(3+))对花青素保存率也有显著性影响(p<0.05),且光照时间越长,H_2O_2、Na_2SO_3浓度越高,作用时间越长,花青素的保存率越低。结论:紫娟茶花青素具有较强的抗氧化活性,但其稳定性相对较差,宜于酸性、低温、避光环境中保存;且保存时应避免接触氧化剂、还原剂及Fe^(3+)、Cu^(2+)、Mg^(2+)等金属离子。

Objective：To study the antioxidant activity and stability of anthocyanins from Zijuan tea.Methods：The antioxidant activity was estimated by the FRAP,ABTS and DPPH assays,and the effect of preservation condition on the stability was evaluated.Results：The anthocyanin concentration was 0.39μg/m L when the FRAP of anthocyanins from Zijuan tea was0.5 mmol/L,and the IC（50）of ABTS^＋·scavenging capacity and DPPH·scavenging capacity of anthocyanins were 0.76 and0.13μg/mL,respectively.The total antioxidant capacity,ABTS^＋·scavenging capacity and DPPH·scavenging capacity of anthocyanins were positively correlated with anthocyanins concentration in the range of test concentration,and were stronger than those of VC,respectively.The p H value had significant affects on the color and absorption spectra of anthocyanins solution,and the anthocyanins were relatively stable when p H≤6.0.With the increasing of temperature and storing time prolonged,the preservation rate of anthocyanins from Zijuan tea gradually decreased（p〈0.05）.The light,oxidant,reductantand metal ions（Fe^3＋,Cu^2＋,Mg^2＋,Ca^2＋,Al^3＋）also significantly affected the stability of anthocyanins（p〈0.05）,and the longer light time,the higher the concentration of H2O2and Na2SO3and the longer storing time,the lower the preservation rate of anthocyanins.Conclusions：The anthocyanins from Zijuan tea had strong antioxidant activity,but their stability were relatively poor.They should be stored under low-temperature and acid environment without light,away from oxidant,reductant and Fe^3＋,Cu^2＋,Mg^2＋ and metal ion and so on.