近红外（NIR）光谱法测定完整苹果糖的含量

介绍一种快速分析完整苹果糖分的新方法──近红外光谱法。在波长９１０ｎｍ附近，高、中、低糖含量的二阶导数光谱之间有明显差异，该波长选作定标的第一波长。经９１０ｎｍ、８８４ｎｍ、８４３ｎｍ、９９１ｎｍ四波长线性回归分析，其相关系数为０．９８４，标准误差为０．３６０，检验时的标准误差为０．４５０，离差为０．１１。ＮＩＲ光谱法在实际应用中可满足完整苹果糖含量的测定精度。

Determination of Sugar Content in Apples by Near Infrared Spectroscopy

In this paper a fast nondestructive analytical mathod to measure sugar content in intact apples-near infrared spectroscopy (NIRS) was introduced. There were clear differences among the NIR second derivative spectra of samples with high, medium, and low Brix values in the 910um wavelength region. This wavelength was characteristic of sucrose and therefore selected as the first calibration wavelength. The highest multiple correlation coefficient of 0. 984um was obtained in the linear regression equation that included four optical terms of d2 log (1/R) at 910um, 884um, 843um and 991um and the standard error of calibration (SEC)was 0.36 Brix. A bias-corrected standard error of prediction (SEP) was 0. 45 Brix with a bias of 0. 11 Brix, suggesting that the NIR method to be practical in determining sugar content in intact apples with sufficient accuracy.