Physicochemical and Chemometric Characterization of Gum Arabic from A. senegal and A. seyal in the Chari-Baguirmi Region, Chad

Abstract

Gum arabic is a natural hydrocolloid mainly obtained from Acacia senegal and Acacia seyal, widely used in the food, pharmaceutical and cosmetic industries for its functional properties. This study aims to characterize and discriminate gums from these two species collected in the Chari-Baguirmi province (Chad), by combining standardized physicochemical analyses following FAO (2018) specifications and AOAC (2010) official methods with multivariate chemometric approaches (Principal Component Analysis, PCA; Partial Least Squares – Discriminant Analysis, PLS-DA; Hierarchical Cluster Analysis, HCA). Moisture, ash, insoluble matter, pH and optical rotation were measured on 24 samples comprising A. senegal (n = 12) and A. seyal (n = 12). A. seyal shows a higher mean moisture content (12.43 ± 0.54 %), whereas A. senegal exhibits higher ash content (1.38 ± 0.19 %) and optical rotation (2.20 ± 1.65°).  Welch’s t-tests (P < 0.05) confirmed that differences in moisture and ash between species are statistically significant. PCA explains 78.09 % of the total variance on the first two components and reveals a clear separation between the species. The PLS-DA, statistically validated by cross-validation, confirms this discrimination and identifies moisture and ash as the most discriminant variables, while HCA reveals two homogeneous, non-overlapping groups. This work therefore fills an important gap by providing the first combined physicochemical and chemometric characterization of Chari-Baguirmi gum arabic from both species in direct relation to international quality standards.