Résumé
Citrus juices and fruits, highly consumed worldwide, represent a significant dietary source of pro-vitamin A carotenoids such as 0-cryptoxanthin which could contribute with vitamins and polyphenols to the beneficial health effects of Citrus fruits. In order to promote a Citrus clementina concentrate specially enriched in 0- cryptoxanthin and obtained by a cross-flow microfiltration [1], the aim of the present work was to assess carotenoid bioaccessibility from Clementine juices versus their concentrates. Pro-vitamin A carotenoids from commercial and fresh juices and their respective concentrates were analyzed by HPLC and their bioaccessibility was investigated using an in vitro digestion model. The main carotenoid 0-cryptoxanthin present in both juices and concentrates was concentrated approximately 8-fold (from 43.3 to 55.2 mg/kg). A medium content of 0- carotene was recovered but was also concentrated 6 to 9-fold (from 6.6 to 9.5 mg/kg) compared to the initial carotenoid profile of commercial and fresh juices. Bioaccessibility of pro-vitamin A carotenoids was greater from commercial juice and its concentrate than from fresh juice and its concentrate (18.9 vs 14.9 % for commercial; 6.3 vs 2.5 % for fresh). Dietary soluble fiber contents such as pectins and percentages of pulp were inversely associated with carotenoid bioaccessibility and were higher in the fresh products (J2, C2) compared to the commercial products (J1, C1) (Figure 1). Furthermore, pectin contents of the concentrates were correlated to higher micelle size. Thus, thermal treatment of pulp matrix during industrial juice production seemed to have a major role to enhance carotenoid bioaccessibility. We suggest that pectin could impair carotenoid micellarization by leading to an increase in micelle size observed for both concentrates. (Résumé d'auteur)