The effect of pectin on in vitro β-carotene bioaccessibility and lipid digestion in low fat emulsions

In this work, we investigated how pectin with different DM, with or without the presence of an additional emulsifier (L-alpha-phosphatidylcholine), influences on the one hand the in vitro bioaccessibility of beta-carotene, loaded in the oil phase of an oil-in-water emulsion, and on the other hand the lipid digestion. As a consequence, the relation between the beta-carotene bioaccessibility and the lipid digestion was investigated as well. For this research, two types of oil-in-water emulsions have been investigated. The first type contained 5% olive oil enriched with beta-carotene and water in which only 2% citrus pectin (CP) (with a DM of 99%, 66% or 14%) was dissolved. In this type, only pectin is present that can function as emulsifier. The second type contained 5% enriched oil and water in which 1% L-alpha-phosphatidylcholine and 0 or 2% CP (with a DM of 99%, 66% or 14%) were dissolved. Results show that the influence of pectin DM on the in vitro beta-carotene bioaccessibility (incorporation of beta-carotene in the micelles) and the lipid digestion (incorporation of free fatty acids (FFAs) and monoacylglycerols (MAGs) in the micelles) was dependent on the presence of phosphatidylcholine but was less dependent on the particle size (distributions) or the viscosity. In the emulsions with phosphatidylcholine, an increase of on the one hand the incorporation of beta-carotene and on the other hand the incorporation of FFAs and MAGs in the micelles was seen by decreasing the DM of the citrus pectin from 99% to 66%, whereas both incorporations decreased again by decreasing the DM further to 14%. In the emulsions without phosphatidylcholine, an increase of the incorporation of beta-carotene into the micelles was seen by decreasing the DM. On the contrary, the incorporation of FFAs and MAGs into the micelles remained. This means that there was a clear relation between the incorporation of beta-carotene and the incorporation of FFAs and MAGs in the micelles for the emulsions without phosphatidylcholine, whereas this was not the case for the emulsions containing phosphatidylcholine. (C) 2015 Elsevier Ltd. All rights reserved.