This thesis is an investigation of mucus interactions with different food delivery systems in vitro to understand the effect of intestinal mucus layer on bioefficacy of bioactive compounds. Milk proteins and liposomes were employed as carriers for model bioactives, Epigallocatechin-3-gallate and β-carotene. Mucus was harvested from mucin producing human intestine cell line—HT29-MTX. Liposomes were prepared from milk and soy phospholipids using microfluidizer, their physicochemical properties were characterized. Mucus interactions with bioactives and matrices were studied on an air/liquid interface by drop shape tensiometry, where interactions were shown by the changes of interfacial tension and dilational viscoelasticity. The bioactives uptake was conducted on cells models with/without mucus present, where higher uptake was found in mucus free Caco-2 cells. These results clearly indicated that specific interactions between mucus and food components need to be taken into account and studied to better understand the absorption behaviour of bioactives during digestion.