Research on drying kinetics, microstructure, and flavor changes of areca nut drying process based on water molecule migration

This study utilized LF-NMR, SEM, and GC × GC-TOFMS to analyze the distribution of water molecules, microstructure, and volatile compounds during drying process of areca nuts. A drying kinetic model was also established. The results showed that during drying, free water on the surface of the areca nut is expelled first, followed by the migration of moisture from the interior to the surface. In blanched areca nuts, a portion of free water is converted into bound water during 0–16 h drying stage. The fiber layers becoming more ordered, dense and compact as drying time increases. Blanching treatment and higher drying temperatures effectively reduce drying time and E_a. The Page model for drying kinetics demonstrated high fitting accuracy for the areca nut drying process with Pearson correlation coefficients and R² values exceeding 0.99 and 0.98. Aldehydes were identified as the primary contributors to the characteristic “fresh aroma” of fresh areca nuts, while hydrocarbons were the main source of the “intense aroma” in dried blanched areca nuts. Drying significantly influenced the relative concentrations of aldehydes and hydrocarbons in areca nuts.