黑糯玉米芯花色苷提取工艺优化及抗氧化活性研究
Optimization of extraction technique and antioxidant activity determination of anthocyanins from black glutinous corncob
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摘要: 以黑糯玉米芯为实验对象,以花色苷提取液的吸光值作为提取效果指标,采用响应面法优化了黑糯玉米芯中花色苷的提取工艺条件。在单因素实验的基础上,采用响应面分析法中的Box-Behnken模式进行三因素三水平的实验设计,结果表明:当乙醇浓度62%,液料比24∶1(m L/g),提取温度47℃,提取时间为120 min,p H为2时,黑糯玉米芯花色苷提取效果最好;在该条件下,采用p H示差法测得到黑糯玉米芯中花色苷含量为57.29 mg/g。通过高效液相色谱-二极管阵列-电喷雾-串联质谱法鉴定了黑糯玉米芯中花色苷的组成,主要为三种花色苷:矢车菊素-3-葡萄糖苷、天葵色素-3-葡萄糖苷、芍药色素-3-葡萄糖苷。抗氧化活性实验表明:黑糯玉米芯花色苷提取物具有一定的清除DPPH自由基和ABTS自由基的能力,同时也显示了较强的还原能力和铁还原力。Abstract: The UV absorbance of extracting solution was used to measure the content of anthocyanins from black glutinous corncob.Response surface analysis method was also used to optimize the extraction condition of black glutinous corncob anthocyanins.Based on the single factor experiments, the interaction of the respective variables and their influence on the extraction effect were studied using Box-Benhnken central composite design and response surface analysis.Results showed that the optimum condition was as follows: the ethanol concentration 62%, liquid-solid ratio 24 ∶ 1, temperature 47 ℃, water-bath time 120 min, p H2.Hence, the maximal content of anthocyanins from dry black glutinous corncob was determined, which was57.29 mg/g. In this paper, high performance liquid chromatography with diode array detection combined with electrospray ionization tandem mass spectrometry ( HPLC-DAD-ESI-MS/MS) was used to analyze the extracted anthocyanidin composition. Three mian anthocyanins were identified: cyanidin-3-glucoside, pelargondin-3-glucoside, and petunidin-3-glucoside.The antioxidant activity experiments indicated that anthocyanins from black glutinous corncob possessed certain ability to scavenge DPPH and ABTS free radical, meanwhile the anthocyanins also showed strong reducing power and ferric reducing power.