电化学阻抗法预测油脂货架期

提出了一种预测油脂货架期的电化学阻抗法。在25 m L 1.0×10-3mol/L Li Cl-乙醇支持电解质中,扰动电压5 m V,频率范围5 Hz~600 k Hz,采用常规三电极系统,测量橄榄油和红花籽油的电化学阻抗谱,发现它们和过氧化值均与时间存在一定的相互对应关系。在此基础上建立了油脂货架期的预测模型。结果表明,该模型所预测的橄榄油的预测货架期为176~188 d,红花籽油的预测货架期15~18 d。而橄榄油和红花籽油的实际货架期分别为184 d和15 d,均与预测货架期较为接近。本研究所建立的方法具有灵敏、快速、操作简便和省时省样等特点。

Prediction of the Shelf-life of Oil with Electrochemical Impedance Spectroscopy

A novel method to predict the shelf-life of oil with EIS (electrochemical impedance spectroscopy) was proposed. In the proper experimental conditions, 25 mL 1.0×10-3 mol/L LiCl- ethanol of supporting electrolyte, disturbance voltage 5 mV, and frequency range 5 Hz ~ 600 kHz, the impedance spectra of olive oil and safflower oil were determined with normal 3 - electrods system. The experimental results indicated that both the impedances decreasing and the POVs increasing were corresponded with time. Then, a model was established to predict the shelf-life of oils. The shelf-lives of olive oil and safflower seed oil predicted by the model were 176 ~ 188 days and 15 ~ 18 days, respectively. The actual shelf lives of olive oil and safflower seed oil, which very close to the predicted data, were 184 day and 15 days, respectively. The proposed method has some special characteristics, such as simplicity, rapidity, and sensitivity.