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Permanent link (DOI): https://doi.org/10.7939/R3H708819

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CHROMATOGRAPHY APPROACHES FOR ANALYZING FRYING OILS AND ASSESSING THE ANTIOXIDATIVE ABILITY OF SITOSTEROL Open Access

Descriptions

Other title
Subject/Keyword
Sterols
HPSEC
Oils
Antioxidants
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Singh, Ashutosh
Supervisor and department
Vasanthan, Thavaratnam
Examining committee member and department
Ullah, Aman (AFNS Department)
Weselake, Randall (AFNS Department)
Temelli, Feral (AFNS Department)
Lampi, Anna (University of Helsinki)
Department
Department of Agricultural, Food, and Nutritional Science
Specialization
Food Science and Technology
Date accepted
2013-09-29T20:55:53Z
Graduation date
2013-11
Degree
Doctor of Philosophy
Degree level
Doctoral
Abstract
The novel utility of sitosterol as an antioxidant in frying oils is explained mechanistically based on physical organic chemistry principles. The antioxidative effect of sitosterol is attributed to the conversion of sterol to steradiene by the 1, 2 elimination of water, which may be catalyzed by hydronium ions resulting from atmospheric moisture present at the air–oil interface. Release of protons, allylic to the conjugated diene system in steradiene, may be responsible for interacting with and terminating lipid oxidation chains. A corresponding increase in the extent of triglyceride (TG) ester hydrolysis is further evidence of release of water in the system resulting from the conversion of sterol to steradiene. High Performance Size Exclusion Chromatography (HPSEC) was used to assess the impact of sitosterol on the extent of TG polymerization in frying oils. A reverse phase C30 column, with longer alkyl chain length coupled with thicker and densely bonded phases, was used to further improve separation and identification of lipid oxidation products. A new adsorption chromatography method using hydrated silica cartridges and solvents, acetonitrile, dichloromethane and tetrahydrofuran, was developed for the measurement of polar content as an indicator of the extent of deterioration in frying oils. Concerns are growing over the potential detrimental effects of lipid oxidation products in frying oils and the ineffectiveness of the available antioxidants at frying temperatures. The potential role of sitosterol as a natural, safe and heat–stable antioxidant in frying oils is an important development for the food processing industry.
Language
English
DOI
doi:10.7939/R3H708819
Rights
Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
Citation for previous publication
Singh, A. (2013) Sitosterol as an antioxidant in frying oils Food Chemistry 137, 62–67

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