TitleProtein modifications in baked versus fried tortilla chips
NameDong, Yuan (author), Schaich, Karen (chair), HO, CHI-TANG (internal member), Frenkel, Chaim (outside member), Rutgers University, Graduate School - New Brunswick,
Lipids in human nutrition,
DescriptionLipid oxidation is recognized as the greatest problem in chemical stabilization of processed foods during storage. Lipid co-oxidations caused by reactions of lipid oxidation intermediates and products with other molecules, particularly proteins, are known, but their impact on food quality (production of off-flavors and odors, loss of color and nutritional value, and texture deterioration) remains largely unexplored, and relatively little is known about the mechanisms involved. However, it is likely that co-oxidations account for much of the “damage” normally attributed to lipid oxidation and provide footprints of lipid oxidation that are not detected in general assays of lipid oxidation. In this research, primary experiments have compared the difference between proteins in baked and fried tortilla chips to distinguish thermal effects of processing from co-oxidation by lipids. Preliminary results showed little difference in protein solubility in fresh baked or fried chips, yet gel electrophoresis revealed significant lipid-mediated differences in disulfide cross-linking in fried chips even immediately after processing without incubations. Schiff base formation was present, but only at low levels, indicating that it is not a major source of cross-linking in early stages of oxidation. Cross-linking continued to develop even more extensively in fried chips during storage at 40 and 60 ºC, and included free radical in addition to disulfide cross-linking. Western blots revealed the presence of protein carbonyls, important co-oxidation products, in most protein fractions in tortilla chips and notably in zeins. Surprisingly, more carbonyls were observed in baked chips with lower lipid content. To determine the connections between these protein changes and lipids, lipid oxidation is being followed in all systems by lipids extractability, free fatty acids, aldehydes and peroxides.
NoteIncludes bibliographical references
Noteby Yuan Dong
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.