Abstract/Details

Potential antioxidant effects of wheat-based cereal extracts on iron-induced phosphytidylcholine liposome oxidation


1999 1999

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Abstract (summary)

The purpose of this work was to study the effectiveness of diet derived antioxidants from wheat based aqueous cereal extracts under simulated gastrointestinal pH conditions and to monitor their effectiveness in modulating iron mediated oxidation which has been suggested as a risk factor in chronic disease.

Wheat based breakfast cereals of composition ranging from whole grain to a refined flour product were analyzed for potential antioxidant effects. The breakfast cereals were extracted under aqueous conditions and the resulting extracts were tested for their ability to inhibit phosphatidylcholine liposome oxidation. The extent of oxidation was monitored by measuring the formation of thiobarbituric acid reaction substances (TBARS) and lipid peroxides. The aqueous extracts were analyzed using solvent extraction, molecular weight fractionation, phytate analysis, soluble fiber analysis, and total phenolics assay to determine the types of compounds responsible for the antioxidant activity. The state and modulation of iron before and after simulated gastrointestinal pH changes was monitored using atomic absorption spectrometry and the bathophenanthroline test.

The aqueous extracts from the whole grain wheat and wheat bran breakfast cereals displayed considerable inhibition to lipid oxidation, while the wheat flour product was less effective. Following molecular weight fractionation the high molecular weight fraction was found to retain most of the antioxidative properties. The aqueous extracts subjected to solvent extraction with chloroform resulted in an organic extract containing non-polar compounds found in the aqueous extract. The antioxidant activity of this organic extract was minimal suggesting that the majority of compounds responsible for inhibiting oxidation are polar. Phytate analysis along with the use of a non-metal catalyst revealed that the antioxidant mechanism is not solely due to metal chelation. Precipitation and isolation of soluble fiber from the aqueous extracts were found to have no effect on oxidation. The total phenolics assay indicated that high concentrations of phenolics are present in the aqueous cereal extracts and appear to contribute to the inhibition of lipid oxidation. Simulated gastrointestinal pH conditions resulted in a significant increase in antioxidant activity for all aqueous cereal extracts including the low molecular weight (molecular mass <3,000 Da) fraction following ultrafiltration.

Simulated gastrointestinal pH conditions resulted in the solubilization of iron in the cereals fortified with elemental iron. This increase in soluble iron was minimal and was found to exist complexed and not in a free ionic state. The solubilized iron following gastrointestinal pH conditions did not significantly effect the oxidation rate of phophatidy1choline liposomes in the model system. The chemical state of iron in the cereal product which was fortified with ferric phosphate was uneffected by the simulated gastrointestinal pH conditions and remained insoluble.

Indexing (details)


Subject
Food science;
Cellular biology;
Anatomy & physiology;
Animals;
Biochemistry
Classification
0359: Food science
0379: Cellular biology
0433: Anatomy & physiology
0433: Animals
0487: Biochemistry
Identifier / keyword
Pure sciences, Biological sciences, Antioxidant, Cereal extracts, Iron, Liposome oxidation, Phosphytidylcholine, Wheat-based
Title
Potential antioxidant effects of wheat-based cereal extracts on iron-induced phosphytidylcholine liposome oxidation
Author
Baublis, Alan Joseph
Number of pages
130
Publication year
1999
Degree date
1999
School code
0118
Source
DAI-B 60/02, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780599199125, 0599199121
Advisor
Clydesdale, Fergus M.
University/institution
University of Massachusetts Amherst
University location
United States -- Massachusetts
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
9920582
ProQuest document ID
304516124
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304516124
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