The impact of wheat bran on vitamin A bioaccessibility in lipid-containing systems

Wheat bran can stabilise vitamin A (retinyl palmitate), making retinyl palmitate/oil/bran mixtures interesting additives for food fortification. However, vitamin A bioaccessibility in these systems remained unstudied. We investigated if native and toasted wheat bran hamper vitamin A bioaccessibility in bulk and emulsified oil-based systems. Vitamin A bioaccessibility was higher in emulsified (12-45%) than in bulk oil-based systems (6-9%), due to more extensive lipid digestion in emulsified (82-83%) than in bulk oil-based systems (56-59%). For bulk oil, wheat bran did not affect vitamin A bioaccessibility. For emulsified oil, toasted and native wheat bran reduced vitamin A bioaccessibility from 45% to 30% and to 12%, respectively. This was attributed to a reduced vitamin A micelle incorporation upon bran addition and a low vitamin A stability upon native bran addition. Thus, the success of bran addition for enhancing vitamin A uptake depends on its stabilising effect during storage and its impact on bioaccessibility.