Effects of hot air drying on drying kinetics, quality and flavor changes of Fructus aurantii

Abstract

This study aimed to evaluate the effect of hot air drying on drying kinetics, quality and flavor changes of Fructus aurantii. The results showed that Midilli model (R² = 0.9995, RMSE = 6.16 × 10⁻⁹, χ² = 7.62 × 10⁻⁵) was the best model for hot air drying of Fructus aurantii, and the effective moisture diffusion coefficient (D_eff) and activation energy (Ea) of hot air drying process was 2.63 × 10⁻⁵ - 6.61 × 10⁻⁴ m²/s and 42.36 KJ/moL, respectively. The HS-GC-MS and E-nose techniques were used to evaluate the changes in volatile components and aromatic characteristics. The results of HS-GC-MS showed that linalool content was 6.69%, 5.32% and 5.10% at 50°C, 60°C and 70°C respectively, showing a decreasing trend. Flavor radar fingerprint map showed that sensors S13, S12 and S2 have obviously higher response values, S11 , S5, S4 and S9 have higher response values, but other sensors have no obvious response values. PCA analysis showed that the first principal component (PC1) and the second principal component (PC2) accounted for 57.38% and 22.59% respectively, and the cumulative variance contribution rate was 87.1% (> 85%). The results of flavor radar fingerprint and PCA showed that the drying process obviously changed the aroma characteristics. The overall results showed that hot air drying at 50-60°C could effectively improve the final quality of dried Fructus Aurantii by maintaining flavor characteristics.

Keywords:

• Fructus auranti
• Hot air drying
• Kinetics
• HS-GC-MS
• E-nose