Effects of Microwave Intensity on Carotenoid Bioavailability in Carrot and Pumpkin during Microwave Vacuum Drying

In order to understand the effect of microwave intensity on the bioavailability of carotenoids in carrot and pumpkin during microwave vacuum drying (MVD), the changes of carotenoid bioavailability were evaluated by static in vitro simulated digestion model, and the changes of cell wall microstructure were observed by transmission electron microscope (TEM) and optical microscope. The results showed that the cell walls of carrot and pumpkin were broken and the chromosomal structure was damaged seriously after MVD. After simulated digestion in vitro, the cell structure of the digestive juice of carrot and pumpkin was destroyed obviously, and the cell wall was broken seriously. The content of carotenoids released from the cells into the digestive juice was significantly higher than that of fresh samples. The bioavailability of carotenoids first increased and then decreased with the increase of microwave intensity. When the microwave intensity was 9 W/g, carotenoids in carrot and pumpkin had higher bioavailability, and the bioavailability of β-carotene significantly increased by 12.02 and 24.2 times compared with fresh samples(P<0.05). Therefore, the appropriate microwave intensity is helpful to improve the bioavailability of carotenoids in vegetables.