Impact of microwave drying at different powers on the drying kinetics, physicochemical properties, and flavor attributes of Aurantii Fructus

The study investigated the impact of microwave drying (MD) on the drying characteristics, physicochemical properties, and flavor attributes of Aurantii fructus (AF). The Midilli model was identified as the optimal model for predicting drying. While MD at 240 W exhibited a color closest to the vacuum freeze-dried (VFD) samples, samples treated with MD at 480 W demonstrated superior physicochemical properties. The 480 W group exhibited the highest content of total polyphenol (42.90 ± 0.77 mg/g), total flavonoid (34.19 ± 3.43 mg/g), naringin (81.05 ± 0.50 mg/g), and neohesperidin (75.05 ± 0.52 mg/g), reaching 3.43, 1.44, 1.22, and 1.08 times those of VFD samples. It also showed the strongest antioxidant activity, with DPPH radical scavenging capacity (69.44 ± 2.00 μmol/g) and ferric reducing antioxidant capacity (104.90 ± 2.07 μmol/g) being 1.61 and 1.63 times those of VFD samples, respectively. Analysis of volatile components identified alkenes as the primary substances, with D-limonene showing the highest relative content at 400 W and at 480 W. Overall, 480 W is considered a suitable microwave power for drying AF. This finding provides new insights for the quality assessment of aromatic Chinese medicinal materials.