Effect of different drying methods on drying kinetics, nutrient content, and microbial content of apricot slices

The selection of a suitable drying method is critical for preserving the quality and safety of apricots (Prunus armeniaca 'Diao Gan'), especially in regions where traditional open-air drying is still widely used. This study compared four drying methods, open-air drying (SD), hot-air drying (HAD), infrared drying (IRD), and infrared vacuum pulsation drying (IR-PVD), by evaluating drying kinetics, effective moisture diffusivity, color, texture, shrinkage, rehydration, nutrient retention, antioxidant capacity, and microbial content of apricot slices. IR-PVD achieved the shortest drying time (16.53 h), followed by IRD (18.15 h), HAD (22.35 h), and SD (68 h), and produced the highest effective moisture diffusion coefficient (9.18 × 10 -9 m 2 s -1 ). IR-PVD also maintained the best overall quality, with the lowest color difference (14.38), browning degree (0.47), hardness (13.89 N), shrinkage (40.85%), and microbial counts (1.15 Log10 CFU g -1 bacteria, 1.43 Log10 CFU g -1 fungi, and undetectable coliforms), as well as the highest color saturation (59.94), rehydration capacity (3.43 g g -1 ), elasticity (3.67), total phenols (12.76 mg GAE g -1 ), total flavonoids (3.94 mg rutin g -1 ), carotenoids (27.68 mg 100 g -1 ), DPPH activity (20.15 mmol Trolox g -1 ), and ABTS activity (31.69 mmol Trolox g -1 ). These results indicate that IR-PVD can shorten processing time while improving nutrient retention, appearance, texture, and microbial safety. The method has practical potential for industrial dried-apricot production, although future work should evaluate energy consumption, economic feasibility, scale-up stability, and storage performance.