Abstract
Objectives
Carotenoids which are rich in fruits and vegetables, are known for their health-promoting benefits. However, due to their hydrophobicity, carotenoids are poorly absorbed in human body and there is a need to improve their absorption. This study aimed to evaluate the effects of the emulsification and the type of dietary fat on the bioaccessibility of carotenoids from vegetable salads.
Methods
Oil-in-water emulsions were formed using the high-pressure homogenizer with whey protein isolate as the emulsifier. A mixture of raw vegetable salads, including tomatoes, baby spinach, carrots, romaine lettuce and Chinese wolfberry, were co-digested with 4 different types of dietary fats: olive oil-in-water emulsion (OLE), olive oil-water mixture (OLN), coconut oil-in-water emulsion (COE) and coconut oil-water mixture (CON). The bioaccessibility of 5 main
carotenoids (lutein, zeaxanthin, α-carotene, β-carotene and lycopene) was evaluated via a simulated in-vitro gastrointestinal model and the carotenoids were detected by high-performance liquid chromatography.
Results
The bioaccessibility (mean ± SD) of total carotenoids was enhanced when vegetable salads were co-digested with the oil-in-water emulsion (23.5 ± 2.8%) than the oil-water mixture (15.4 ± 7.6%) (P < 0.05). Specifically, OLE showed an increase in the bioaccessibility of α-carotene (OLE: 24.5 ± 2.4%, OLN: 19.0 ± 0.6%, P < 0.05) and β-carotene (OLE: 20.4 ± 1.0%, OLN: 14.6 ± 2.5%, P < 0.05), compared to OLN, while no differences were observed for lutein, zeaxanthin and lycopene. On the other hand, COE resulted in higher bioaccessibility of all the individual carotenoids as compared to CON (P < 0.05), except for the zeaxanthin. Overall, the bioaccessibility of total carotenoids was higher with olive oil (24.0 ± 2.8%) than coconut oil (14.9 ± 6.9%) (P < 0.05).
Conclusions
Findings from this study indicate that emulsification of dietary fats and olive oil enhance the bioaccessibility of carotenoids. Using excipient olive oil-in-water emulsion in particular, may be a potential way to improve the absorption of carotenoids when it is added into the carotenoids-rich vegetable salads as salads dressing.
Funding Sources
National University of Singapore, Agency for Science, Technology and Research.
Silver-mediated separation of polyunsaturated fatty acids by oil-in-water emulsion liquid membranes.
