Kinetic approach to study the relation between in vitro lipid digestion and carotenoid bioaccessibility in emulsions with different oil unsaturation degree

Emulsions were prepared with oils (5% w/v) differing in unsaturation degree (olive, soybean or linseed oil) and sucrose ester (0.5% w/v) used as emulsifier. The oils studied were enriched with carotenoids from carrot or tomato purees. All emulsions were in vitro digested and characterised at the level of lipolysis and carotenoid micellarisation kinetics in the small intestinal phase. Olive oil emulsions led to a faster and more extensive lipolysis and carotenoid bioaccessibility compared to soybean and linseed oil emulsions. Monounsaturated fatty acids present in olive oil might be more hydrophobic in comparison to polyunsaturated fatty acids from soybean or linseed oil, leading to micelles with greater capacity of solubilising hydrophobic carotenoids. The obtained results evidence the potential of the oil unsaturation degree for modulating lipolysis and carotenoid bioaccessibility in the gastrointestinal tract and moreover, exemplify the relevance of a kinetic approach including modelling of different lipolysis species to quantitatively prove their interrelation.