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为确定紫甘薯花青素在不同储存溶剂中的稳定性,分别采用不同浓度的乙醇水溶液(0、10%、20%和50%)模拟紫甘薯花青素在水、啤酒、葡萄酒和白酒中的储存条件,通过化学动力学研究方法研究了紫甘薯花青素在不同溶剂中的降解规律。结果表明:在去离子水、10%乙醇、20%乙醇和50%乙醇中紫甘薯花青素的降解均符合一级反应动力学模型,半衰期(t1/2)和D值随着温度的升高而降低,Z值随着乙醇浓度的升高而升高。通过Arhenius方程和Eyring-Polanyi模型计算出降解活化能、焓值和熵值,乙醇浓度为0、10%、20%、50%时,降解活化能(Ea)分别为83.46、78.53、78.09、75.33 kJ/mol,焓值(ΔH)分别为77.33、72.41、71.97、69.21 kJ/(mol·K),熵值(ΔS)分别为180.81、188.37、189.94、193.57 J/(mol·K),随着乙醇浓度的升高,紫甘薯花青素的Ea和ΔH降低、ΔS升高,说明随着乙醇浓度的升高,紫甘薯花青素对温度的敏感性增强。这些研究结果为紫甘薯花青素在食品、药品和化妆品等行业中的应用奠定了一定的理论基础。
To determine the stability of purple sweet potato anthocyanins in different storage solvents, different concentrations of ethanol aqueous solution (0,10%, 20% and 50%) were used to simulate the purple sweet potato anthocyanins in water, beer, wine and white wine The storage conditions of purple sweet potato anthocyanins in different solvents were studied by chemical kinetic methods. The results showed that the degradation of anthocyanin in purple sweet potato in deionized water, 10% ethanol, 20% ethanol and 50% ethanol all accorded with the first-order reaction kinetics model. The half-life (t1 / 2) Higher and lower, Z value increased with the increase of ethanol concentration. The activation energy, enthalpy and entropy of degradation were calculated by Arhenius equation and Eyring-Polanyi model. The degradation activation energies (Ea) were 83.46, 78.53, 78.09 and 75.33 respectively at ethanol concentration of 0, 10%, 20% and 50% The enthalpy (ΔH) was 77.33, 72.41, 71.97 and 69.21 kJ / mol · K, respectively, and the entropic values were 180.81, 188.37, 189.94 and 193.57 J / mol · K, respectively. Ethanol concentration increased, purple sweet potato anthocyanin Ea and ΔH decreased, ΔS increased, indicating that with the increase of ethanol concentration, purple sweet potato anthocyanins increased sensitivity to temperature. These findings provide a theoretical basis for the application of purple sweet potato anthocyanins in food, medicine and cosmetics industries.