Abstract: The effects of processing methods and mastication levels (chewing 5, 15 and 30 times) on the digestion characteristics and bioavailability of carotenoids in restructured carrot chips, carrot chips and fresh carrots were investigated by using an in vitro digestion model. Significant differences in the average particle size of the digesta of fresh carrots and carrot chips were observed (P < 0.05). The average particle size of the digesta was gradually increased with increasing extent of mastication, indicating that more particles suspended in the digesta after mastication could readily cause fluocculation. Confocal fluorescence microscopic observation showed that lipid droplets were bound to the samples to form large aggregates in the mouth. Lipid droplets were dispersed in the gastric digesta, and then were digested to form micelles in the small intestine, which was positively related to the bioavailability of carotenoids. The content of carotenoids was the highest and the bioavailability of carotenoids was the lowest in fresh carrots. However, although the content of carotenoids in restructured carrot chips was lower than that in other chips, the bioavailability of carotenoids in the sample was higher, and chewing degree showed no significant influence on the bioavailability of carotenoids in it (P > 0.05). In conclusion, restructured carrot chips are effective in supplementary carotenoids as a snack food due to the superior digestive behavior and bioavailability of carotenoids.

Key words: carrots, restructured chips, carotenoids, in vitro digestion, bioavailability