Bioaccessibility of carotenes from carrots: Effect of cooking and addition of oil

Food processing and occurrence of dietary lipids are believed to be important and limiting factors for carotenoid bioavailability in humans. In the present study the isolated and combined effects of household cooking and addition of olive oil on the bioaccessibility of carotenes from carrots have been investigated. Although thermal treatment during cooking showed to have a negative impact on the carotenoid content, a positive effect on the micellarisation of carotenes and therefore on their bioaccessibility was found. Carotenes transferred to the digests were micellarised to a higher extent from cooked carrots (52%) than from crude carrots (29%). Addition of olive oil to carrot samples during cooking and before application of the in vitro digestion model had a marked positive effect on the release of carotenes, although the design of the model did not allow the correct estimation of this effect. The higher amounts of micellarised carotenes (80%) were found in the digest prepared from cooked carrots containing 10% olive oil. In general, the inclusion of olive oil during cooking increased the carotenoid extraction and micellarisation in a dose-dependent fashion. Although β-carotene and α-carotene were affected in a similar way by the cooking process, α-carotene appeared to be more efficiently incorporated into the micelles when olive oil was added to the samples. In conclusion, both processing and mainly lipid content (cooking oil in this case) significantly improve carotenoid bioaccessibility from carrots, and therefore may increase bioavailability in humans.Industrial relevanceThe consumption of carotenoid-rich foods such as fruits and vegetables has been associated with a decrease of the risk of developing certain types of degenerative and chronic diseases. Processing of food and the interaction of carotenoids with lipophilic food components or ingredients may modify the amount of the released pigment from the food matrix, and therefore potentially increase or decrease their bioavailability. For this purpose, in the present study we have investigated the effects of cooking and presence of olive oil on the release of carotenes from carrots (as a model food) and their incorporation into absorbable micelles, the bioaccessibility. From the industrial point of view, a better understanding of the factors governing the release of carotenoids and other active components from vegetable foods is of great importance with the aim of optimising the manufacturing processes.