Performance of β-carotene-loaded nanostructured lipid carriers under dynamic in vitro digestion system: Influence of the emulsifier type

A better understanding of how emulsifier type could differently influence the behavior of nanostructured lipid carriers (NLC) under the gastrointestinal digestion process, as well as at the cellular level, is of utmost importance for the NLC-based formulations' optimization and risk assessment in the food field. In this study, NLC composed by fully hydrogenated soybean and high-oleic sunflower oils were prepared using soy lecithin (NLC L-beta) or Tween 80 (NLC T-beta) as an emulsifier. beta-Carotene was entrapped within NLC developed as a promising strategy to overcome beta-carotene's low bioavailability and stability. The effect of emulsifier type on the digestibility of beta-carotene-loaded NLC was evaluated using an in vitro dynamic digestion model mimicking peristalsis motion. The influence of beta-carotene-loaded NLC on cell viability was assessed using Caco-2 cells in vitro. NLC T-beta remained stable in the gastric compartment, presenting particle size (PS) similar to the initial NLC (PS: 245.68 and 218.18 nm, respectively), while NLC L-beta showed lower stability (PS > 1000 nm) in stomach and duodenum phases. NLC T-beta also provided high beta-carotene protection and delivery capacity (i.e., beta-carotene bioaccessibility increased 10-fold). Based on the results of digestion studies, NLC T-beta has shown better physical stability during the passage through the in vitro dynamic gastrointestinal system than NLC L-beta. Moreover, the developed NLC did not compromise cell viability up to 25 mu g/mL of beta-carotene. Thus, the NLC developed proved to be a biocompatible structure and able to incorporate and protect beta-carotene for further food applications.