Role of structural barriers in the in vitro bioaccessibility of anthocyanins in comparison with carotenoids

- Anthocyanin and carotenoid bioaccessibility was monitored in a single plant matrix.
- Samples with increasing level of compound bioencapsulation were included.
- Anthocyanin bioaccessibility was not proportional to level of bioencapsulation.
- Cell wall disruption did not enhance anthocyanin bioaccessibility.
- Mechanical processing had a higher impact on carotenoid bioaccessibility.

Although natural structural barriers are factors limiting nutrient bioaccessibility, their specific role in anthocyanin bioaccessibility is still unknown. To better understand how natural barriers govern bioactive compound bioaccessibility, an experimental approach comparing anthocyanins and carotenoids was designed, using a single plant matrix. Initial results revealed increased anthocyanin bioaccessibility in masticated black carrot. To explain this observation, samples with increasing levels of bioencapsulation (free-compound, homogenized-puree, puree) were examined. While carotenoid bioaccessibility was inversely proportional to the level of bioencapsulation, barrier disruption did not increase anthocyanin bioaccessibility. This means that mechanical processing is of particular importance in the case of carotenoid bioaccessibility. While micelle incorporation is the limiting factor for carotenoid bioaccessibility, anthocyanin degradation under alkaline conditions in the gastrointestinal tract dominates. In the absence of structural barriers, anthocyanin bioaccessibility is greater than that of carotenoids.