Enhancing bioaccessibility and stability of carotenoids from pumpkin peel by nanostructured lipid carriers

Carotenoids were isolated from pumpkin peel powder (PP). Nanoencapsulation was studied to improve their bioaccessibility and stability. Carotenoids of PP showed the highest value of bioaccessibility for free xanthophylls, followed by beta-carotene, di- and mono-esterified xanthophylls. The same trend was observed for carotenoid extract (CE). When CE was encapsulated into lipid nanoparticles and lyophilized (L-CE-NLC), free xanthophylls and beta-carotene showed very similar bioaccessibility values (about 65%), which were higher than those observed for PP and CE. Similarly, the bioaccessibility of esterified carotenoids in L-CE-NLC was comparable and consistently higher than in PP and CE (20 vs. 3%). Then an accelerated stability study (dark and light conditions) was also carried out. In the dark, L-CE-NLC demonstrated a better preservation of antioxidant capacity than a commercial supplement of beta-carotene. In the light, the L-CE-NLC preserved the antioxidant capacity of the CE between 65% and 74% of the initial value. These findings highlight the crucial role of nanoencapsulation in nutraceutical and pharmaceutical fields, especially when carotenoids are used.