Beta-carotene is a carotenoid with a wide spectrum of biological activities (e.g., anti-cancer, anti-hypertensive, and anti-inflammatory). However, because of its extremely high hydrophobicity, it is difficult to incorporate in food formulations and its bioavailability is fairly low. Lipid-based encapsulation colloidal systems such as lipid nanoparticles can help overcome these issues. In this study, beta-caroteneloaded lipid nanoparticles were produced by the phase inversion temperature (PIT) method from 10% cupuacu butter and 20% surfactant (Cremophor RH40 and Span 80). The inversion temperature of the nanoparticles was 74 C and their average diameter was 35 nm. After 100 days of storage, 85% of the initial amount of beta-carotene remained in the nanoparticles; alpha-tocopherol was found to be essential for carotenoid preservation. Comparison of the results of in vitro digestion between static and dynamic systems was performed, and the characteristics of each digestion system led to diverse results in terms of average particle size and beta-carotene bioaccessibility. Although the static system was much simpler than the dynamic system, it could not provide reliable data of the digestibility of the lipid nanoparticles. The bioaccessibility of beta-carotene in the static system was 92%, very similar to the results found in the literature; by comparison, the dynamic system revealed a beta-carotene bioaccessibility of nearly 20%. Despite this discrepancy, the highly realistic conditions of digestion simulated by the dynamic in vitro system indicate that the results of this system are more reliable than those obtained from the simplified static system applied in this research.

Hydrophobic bioactives can be more easily incorporated into food and have their bioavailability enhanced if nanostructured lipid carriers (NLC) are used as carriers. In the present study, betacarotene-loaded NLC were produced by low emulsification using murumuru butter and a mixture of Span 80 and Cremophor RH40 as surfactants. Their average diameter was 35 nm and alpha-tocopherol was required to protect the encapsulated b-carotene. Besides the evaluation of their physicochemical stability, NLC were submitted to dynamic in vitro digestion and cell viability assays with Caco-2 and HEPG cells. The bioaccessibility of beta-carotene in the dynamic system was about 42%. Regarding cell viability, results indicated NLC were toxic to the cell cultures tested. Such high toxicity is probably related to the type of surfactant used and to the extremely reduced particle size, which may have led to an intense and fast permeation of the NLC through the cells. ARTICLE HISTORY