Noninvasive Evaluation of Fructose, Glucose, and Sucrose ‎Contents in Fig Fruits during Development Using Chlorophyll Fluorescence and Chemometrics

The use of chlorophyll fluorescence (ChlF) technique was evaluated on nondestructive measurement of sugar content during fruit development. Multivariate models, principal component analysis (PCA), and partial least-squares regression (PLSR), were developed for the classification and prediction of fructose, glucose, and sucrose in fig fruits. The results of this study showed a significant correlation between fluorescence parameters and sugar content during fruit development. The PCA-ChlF can be used as a fast screening method for discriminating the degree of maturity based on sugar content. In addition, the root mean squared error (RMSE) and coefficient of determination (R2) of PLSR-ChlF for predicting sugar content were 2.01 g 100 g-1 DW and 0.96 for fructose, 1.03 g 100 g-1 DW and 0.99 for glucose, and 0.17 g 100 g-1 DW and 1.00 for sucrose, respectively. Therefore, ChlF combined with chemometrics may be a potential tool to nondestructively evaluate sugar accumulation in not only fig fruits, but also any other chlorophyll-containing fruit during development.