Effects of Drying Techniques and Temperatures on the Amygdalin Content and Its Properties in Apricot Kernel Extracts

This study investigated the effects of drying techniques (oven and vacuum drying) and temperatures (65–150 °C) on the drying behavior, extraction efficiency, and amygdalin content of apricot kernels. Higher drying temperatures significantly reduced the drying time and increased the mass loss. Vacuum drying achieved faster drying rates. Moisture diffusion improved at elevated temperatures with significant falling rate periods. The Midilli model was the best-fit drying kinetic model. Oven drying required a lower activation energy (5.97 kJ/mol) than vacuum drying (22.64 kJ/mol). The amygdalin content in the extracts ranged from 2.2 to 4.2%, with a higher level from vacuum drying at 120 °C. The antioxidant, especially radical scavenging and anti-inflammatory, activities of the kernel extracts strongly correlated with the amygdalin content. Extracts from oven drying at 100 °C and vacuum drying at 120 °C demonstrated the highest bioactivities. Overall, vacuum drying was more effective in maintaining the amygdalin content and enhancing the bioactive properties of apricot kernel extracts.