Nuntarat Boonlao creator Anal, Anil Kumar Chairperson Loc, Thai Nguyen Examination committee Sadiq, Muhammad Bilal Examination committee Her Majesty the Queen's Scholarship Scholarship Donor text series technical report th Pathum Thani, Thailand Asian Institute of Technology 2018 continuing eng 61 leaves : ill. This study aims to evaluate the effects of whey protein isolate (WPI) and xanthan gum (XG) stabilized oil-in-water emulsions loaded with astaxanthin for their physicochemical stability and in-vitro gastrointestinal tract behavior. The formulations of emulsions with different WI and XG concentrations were evaluated. Whey protein isolate concentration was varied from 2 to 5 wt%, while XG was varied from 0 to 0.5 wt%. The result showed that the additions of 0.5 wt% XG with all different WPI concentrations increased the viscosity, reduce creaming and the phase separations. Furthermore, the emulsion with 0.5 wt% XG did not exhibit any phase separation during the storage period of 30 days. The astaxanthin-loaded emulsions were further evaluated for the influences of temperature, pH, ionic concentration and light. Emulsions were found physically stable up to 70 °C. The retention of astaxanthin after processing conditions based on pasteurization was determined at 63 °C and 72 °C under different intervals of time. The retention of astaxanthin was around 80% after heating at 63 °C during 15, 30 and 45 min. However, the highest astaxanthin retention (98%) was found under 72 °C for 15 min. The emulsions were not stable at pH 2-4. Furthermore, emulsions were found physically stable under the different salt concentrations, in the ranges of 0-150 mM. The astaxanthin retention of emulsion exposure to light condition is 78% over 32 h. Additional, emulsions with WPI and WPI+XG were assessed through an in-vitro gastrointestinal model and changes in their particle size, zeta potential were evaluated. The bioaccessibility of astaxanthin incorporated into PI-stabilized emulsion and emulsion with WPI+AG is 46.2 % and 12.6 % respectively. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Food Engineering and Bioprocess Technology Thesis (M. Sc.) - Asian Institute of Technology, 2018 Emulsion Proteins Polysaccharides Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B21327 http://203.159.5.9/ait-thesis/detail.php?q=B21327 190829 20260818114340.0