Reid, Elizabeth2017-04-112017-04-112015-01https://hdl.handle.net/11299/185552University of Minnesota M.S. thesis. January 2015. Major: Food Science. Advisor: Tonya Schoenfuss. 1 computer file (PDF); viii, 141 pages.Low value dairy products such as lactose and acid whey, pose a huge opportunity to be converted into value-added products. This research evaluated the effect of formula and processing conditions on the polymerization of lactose by reactive extrusion into indigestible oligomers. Three citric acid concentrations (2%, 4% and 6%) and two feed rates (15 kg/hr and 30 kg/hr) were evaluated for their effect on the polymerization of lactose. Samples extruded at 15 kg/hr resulted in a higher yield of indigestible oligomers (46.7-56.4%) than at 30 kg/hr (33.7-43.5%). A successful cleanup procedure for Greek yogurt acid whey was developed so that it could be concentrated and drum dried. Heat treating the acid whey resulted in a reduction of protein, fat, and moisture. Washing the condensed whey resulted in a reduction of lactic acid, protein, and a lighter colored drum dried product.enacid wheydietary fiberextrusionGreek yogurtlactoseoligosaccharideThesis or Dissertation