Whey protein isolates (WPI) have been indicated to have potent cholesterol lowering and antioxidative properties. Such effects, however, are not consistently observed, which could be the result of major differences in the processing, isolation and composition of WPI. Moreover, the mechanisms of action or the bioactive component(s) in WPI are poorly understood although the relatively high cysteine content in WPI has been suggested to play an important role. Although high dietary cysteine has been shown to lower plasma homocysteine concentrations, the impact of WPI in this regard has not been investigated. The overall objective of this thesis was to examine the antioxidative and plasma cholesterol and homocysteine lowering properties of two WPI that were produced via different industrial processing and isolation techniques with the milk protein, casein, used as the control protein. We also examined for the mechanism(s) of action of WPI in terms of possible antioxidative, and plasma cholesterol and homocysteine lowering effects. In this regard, the intake of bovine serum albumin (BSA), a major cysteine-rich whey protein was also studied since this protein has been implicated as a key bioactive component for the antioxidant effects of WPI. Four studies were performed. The first involved the characterization of a variety of commercially prepared WPI by high performance capillary electrophoresis for identification of two WPI products that showed major differences in protein composition for subsequent feeding trials. Most of the WPI had similar characteristic electrophoretic profiles, however, significant differences in protein and macronutrient (Ca, Mg, P) composition were noted in two commercial WPI that were chosen as the test proteins in subsequent feeding trials. In the first two feeding studies, hamsters were fed different commercial WPI or milk protein (BSA or casein) containing diets that were either matched or unmatched in terms of macro
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.84301 |
| Date | January 2004 |
| Creators | Nicodemo, Antonio |
| Contributors | Kubow, Stan (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (School of Dietetics and Human Nutrition.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002083308, proquestno: AAINQ98336, Theses scanned by UMI/ProQuest. |
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