Proceedings of International Congress on Bioactive Compounds and International Workshop on Bioactive Compounds
Proceedings of 1st International Congress on Bioactive Compounds and 2nd International Workshop on Bioactive Compounds - Vol. 1 - 2018

Carotenoids and phenolic compounds are bioactive compounds widely distributed in fruits, vegetables and several food products. Despite the concomitant presence of these classes of compounds in foods, interactions between carotenoids and phenolic compounds during digestion that may influence on their respective bioaccessibilities are poorly both understood and reported. The aim of the present study was to assess whether the presence of phenolic compounds might affect the in vitro bioaccessibility and digestive stability of carotenoids in a mimic food system. Two oil-in-water (O/W) emulsions were prepared as mimic food systems, one containing only carotenoids (carotenoid emulsion, CE) and the second containing carotenoids and phenolic compounds (carotenoid-phenolic emulsion, CPE). Commercial frozen pulp of cajá (Spondias mombim), a fruit native from the Central America to the Northeast Brazilian region, was used as a source of natural carotenoids and phenolic compounds to prepare emulsions. Formulations consisting of 2% oil phase (carotenoid-rich soybean oil) and 98% aqueous phase (1.5% Tween 20 aqueous solution with or without phenolic compounds) were homogenized by microfluidization (3 cycles, 9.000 psi) to produce the emulsions, which were subjected to in vitro digestion using the internationally recognized INFOGEST method adapted for carotenoids. Phenolic compounds and carotenoids from emulsions, and carotenoids from chyme and micellar fractions were analyzed by HPLC-DAD-MS/MS. Although prepared with exactly the same amount of carotenoid-rich oil, the total carotenoid content in CE was higher (23 µg/g emulsion) than in CPE (14 µg/g emulsion) (p<0.05). Regarding to the phenolic compounds, a total of 142 µg/mL emulsion was present in CPE, representing a carotenoid-to-phenolic ratio of 1:10 in this system. Carotenoids were stable during digestion, and the recovery of total carotenoids exceeded 95% upon completion of in vitro digestion for both formulations. The HPLC profile of chyme showed a decrease in the concentration of carotenoid diesters and monoesters associated with an increase in the concentration of free xanthophylls after digestion of either emulsion, indicating the occurrence of carotenoid ester hydrolysis during digestion. Nonetheless, hydrolysis was incomplete and both free and esterified carotenoids partitioned into micelles. Regardless the presence of phenolic compounds, the extent of micellarization of free xanthophylls consistently exceeded that of monoesters, which exceeded diesters. The presence of phenolic compounds decreased the bioaccessibility of carotenoids (p<0.05), being the micellarization of carotenes and carotenoid esters impaired in a greater extent. Whereas 51% of the total carotenoids was bioaccessible when in the formulation containing only carotenoids, 28% was bioaccessible in the formulation containing also phenolic compounds. Besides the higher incorporation of both free and esterified forms of carotenoids into micelles, CE also presented higher carotenoid ester hydrolysis after digestion than CPE. This suggests that, in addition to the possible competition with carotenoids for micellarization, phenolic compounds may have inhibited digestive enzymes, although several factors might have contributed to these differences. Our findings indicate a significant negative interaction between polyphenols and carotenoids during in vitro digestion of food mimic systems, which may have important applications for the design and fabrication of food products or emulsion-based delivery systems for bioactive compounds.