Amann, Alexander2016-04-142016-04-142016-02https://hdl.handle.net/11299/178913University of Minnesota M.S. thesis.February 2016. Major: Food Science. Advisor: Devin Peterson. 1 computer file (PDF); ix, 99 pages.Both apple and orange juice were investigated for off-flavor formation after 8 weeks of storage at 35°C. Furfural, p-vinylguaiacol, Furaneol (DMHF), β-fenchyl alcohol, α-terpinolene, α-terpineol, terpinen-4-ol, and methional were selected in orange juice while furfural, 5-methylfurfural, furfuryl alcohol, and β-damascenone were selected as off-flavor markers in apple juice. In orange juice, furfural was shown to be formed predominately from ascorbic acid degradation, and DMHF was formed from the degradation of reducing sugars. In apple juice, 5-MF, furfural, and furfuryl alcohol exhibited carbon labeling from reducing sugars. In orange juice, both GLN and TRP accelerated the formation of furfural, p-vinylguaiacol, Furaneol, α-terpineol, and terpinen-4-ol. In apple juice, both GLN and GABA promoted 5-methylfurfural, furfuryl alcohol, and β-damascenone formation over 8 weeks storage. Understanding the influence of fruit composition on the generation of off-flavors can aid in the development of approaches that yield juice with an improved flavor quality throughout shelf life.enApple JuiceOff-FlavorOlfactometryOrange JuicePathway InvestigationStorageThesis or Dissertation