In vitro approach (solubility and Caco-2 uptake) to compare Cu availability from model cookies

Six model cookies were prepared in order to investigate the possibility of using whole grain raw materials other than wheat (inulin in combination with soy, amaranth, carob, apple dietary fibre or oat dietary fibre) for creating novel cookies with improved copper content and bioavailability. For assessment of copper solubility and intestinal uptake, in vitro enzymolysis approach was combined with Caco-2 cell culture technique and copper concentrations were determined using ICP-AES technique. Results indicate significant increase of the content of total and soluble Cu fractions in all modified cookies (with exception of cookies enriched with oat fibre). Average Cu solubility from investigated samples ranged from 51.6 to 68.9%. The highest Caco-2 cell uptake was determined in soy- and amaranth-enriched cookies. Total Cu content and proteins were determined as promoters of Cu absorption and transport, while addition of pure dietary fibre negatively influenced Cu uptake on the Caco-2 cell monolayer.