Quantitative Determination of Sugar Profiles in Peach Fruit During Storage by an Integrating Sphere System

This work describes the optical approach for the quantitative description of sugar profiles in peaches during storage by using single integrating sphere (SIS). The spectral profiles for the optical properties (light absorption coefficient mu(a) and reduced scattering coefficient mu'(s)) were measured. Correlation analysis between the optical properties and the sugar profiles showed that higher correlated values, with r > 0.640, were found. Furthermore, quantitative models were constructed by Partial Least Squares Regression (PLSR) based on mu(a) and mu'(s) datasets to predict the sugar composition in peach flesh. The predicted results for the sucrose content based on mu(a) datasets by PLSR were better than those based on the mu'(s). For fructose and glucose contents, the predicted models were not very satisfactory due to low concentration in peach flesh, with R-p(2) of 0.721, RMSEP of 0.817 g kg(-1) for fructose and R-p(2) of 0.753 and RMSEP of 0.604 g kg(-1 )for glucose, respectively. The models established by SIS present a simple and efficient strategy for quantitative analysis and may be used as alternative methods for evaluating the quality attributes of different types of fruit.