Abstract: The correlation between food microstructure and in vitro bioaccessibility of carotenes was evaluated for tomato and carrot emulsions (5% olive oil) subjected to high pressure homogenization (HPH) at varying degrees of intensity. The aim was to investigate whether additional mechanical disruption of the food matrix could be utilized to further increase the carotene bioaccessibility of an already pre-processed material. The carotene bioaccessibility of the samples was measured after simulated in vitro digestion, carotene release to the oil phase was estimated by Confocal Raman spectroscopy and, to measure active uptake of carotenes, Caco-2 cells were incubated with the digesta of selected samples. HPH did not notably affect the retention of carotenes or ascorbic acid but significantly increased both the release and micellar incorporation of α- and β-carotene in carrot emulsions 1.5- to 1.6-fold. On the other hand, in vitro bioaccessibility of lycopene from tomato was not increased by HPH under any of the conditions investigated. Instead, the results suggested that lycopene bioaccessibility was limited by a combination of the low solubility of lycopene in dietary lipids and entrapment in the cellular network. Carotene uptake by Caco-2 cells appeared to be mainly dependent upon the carotene concentration of the digesta, but cis-trans isomerization had a significant impact on the micellarization efficiency of carotenes. We therefore conclude that HPH is an interesting option for increasing the bioaccessibility of carotenes from fruits and vegetables while maintaining a high nutrient content, but that the results will depend on both food source and type of carotene.
Practical Application: A better understanding of the correlation between the processing of fruits and vegetables, microstructure and nutrient bioaccessibility can be directly applied in the production of food products with an increased nutritional value.