Evaluation of Carotenoid Bioaccessibility in Selected Dietary Sources Using a Modified INFOGEST In Vitro Digestion Protocol

Abstract This study assessed the bioaccessibility and stability of lutein and other carotenoids in avocado, kiwi, orange, and lamb’s lettuce. A modified INFOGEST in vitro digestion protocol was employed to improve analytical recovery, micellar separation, and quantification of carotenoids. The standardized static in vitro digestion model from COST Action INFOGEST was adapted by increasing the sample size to 20 g and applying centrifugation at 20000g for 5 min to enhance micellar transfer. Carotenoids were quantified using high-performance liquid chromatography. Lamb’s lettuce exhibited the highest lutein (4615 μg/100 g) and β-carotene (2156 μg/100 g) contents and showed low recovery and poor β-carotene bioaccessibility (5.1%). Lutein in avocado (172 μg/100 g) showed high recovery (95.9%) and bioaccessibility (55.3%). Kiwi (65 μg/100 g lutein) demonstrated the highest lutein bioaccessibility (71.0%) and good stability (73–80% recovery), with β-carotene bioaccessibility at 36.4%. Orange was rich in β-cryptoxanthin (73 μg/100 g) and zeaxanthin (13 μg/100 g) and exhibited moderate bioaccessibility for violaxanthin (25.3%), β-cryptoxanthin (18.0%), and zeaxanthin (30%). These findings highlight the importance of sample mass and centrifugation parameters in assessing carotenoid bioaccessibility. The results highlight how food matrix and carotenoid type affect bioaccessibility, reinforcing the need to adapt digestion protocols to lipophilic compound properties and the food matrix.