多元校正紫外光谱法测定苹果汁含量研究

研究了多元校正紫外光谱测定苹果汁含量的方法。结果表明,苹果汁含量不同的样品有不同的紫外吸收曲线。含量小于70%时,曲线差异明显,噪音较小。当含量大于70%后,光谱噪音水平升高,不同含量的吸收曲线差异缩小,检测能力下降。利用偏差权重法选取280-365 nm区间的光程进行建模,用主成分分析法来压缩变量,然后用逐步回归法建立苹果汁含量的数学模型,再用完全交互验证法对模型进行验证,结果预测值与真实值相关性良好,偏差较小。通过优化建模条件,建立合适的UV光谱预测模型,可以对苹果汁及其饮料中原果汁含量进行快速检测。

Detection the Concentration in Apple Juice by Ultraviolet-visible Spectroscopy and Multiple Linear Regression Methods

The method for detection the concentration of apple juice by multiple linear regression and UV spectrum was studied.The result indicated that different concentration of apple juice results in different absorbing curve.While the concentration is lower than 70%,the curve has an obvious difference between different concentrations.While the concentration is higher than 70%,UV spectrum's discriminate capability descends along with the increasing of the concentration.The wavelength range from 280 nm to 365 nm was picked out depend on their RSD,and the variables were compressed by PCA(Principal component analysis).The mathematical model was established by stepwise regression,and then be optimized.The result of cross validation indicates that the mathematical model has a fine predict capability.