Effects of processing treatments on physicochemical properties and storage stability of juice treatments and their effect on carotenoid bio-accessibility.

The poor carotenoid bioavailability of fruit and vegetable juice is a problem, since carotenoids are located in the chromoplasts of the plant cells, and their release from food matrix is restricted by surrounding cell membranes and cell walls affecting their bioaccessibility. Carrot and peach are popular vegetables and fruits grown throughout the world and are important sources of dietary carotenoids and fiber. Pectin is a family of heterogeneous polysaccharide with galacturonic acid (GalA) as the main monosaccharide moiety, and it is mostly located in the plant cell walls, so present in fruits and vegetables together with carotenoids. Pectin was reported to have a negative effect on the lipid digestion, thus having potential influences on the digestion and absorption of carotenoids, since carotenoids need to be released from the food matrix, solubilized into the lipid phase, and incorporated into mixed micelles with certain hydrolysates of lipids prior to absorption. However, the correlations between pectin structure and carotenoid bioaccessibility and subsequent bioavailability are unclear. The influences of pectin on the carotenoids during digestion and absorption might also be depending on the food matrix and the mechanisms are deserved to be investigated in different plant materials. The objective is to investigate the correlations between precise pectin structure and the digestion and absorption of carotenoids in combined juices of carrot and peach, aiming for facilitating processing as a tool for developing juice with enhanced level of bioavailable carotenoids. The enzymatic fingerprinting method is applied to get a full view understanding of the pectin structure, and especially the substituents in pectin. The effects of pectin enzymatic hydrolysate on the carotenoid bioaccessibility will also be studied to further develop a targeted enzymatic method to improve their bioaccessibility.