Characterization of iron-promoted lipid oxidation in emulsions

1999 1999

Other formats: Order a copy

Abstract (summary)

Lipids in most foods exist as emulsions, therefore it is important to understand the factors affecting oxidative rancidity in emulsions. The ability of iron to promote lipid oxidation in emulsions can be affected by iron's ability to interact with lipids at the emulsion droplet interface. This research was designed to better understand the factors affecting iron interactions with components of emulsions including lipid and surfactant peroxides. Salmon oil-in-water emulsions stabilized by SDS exhibited greater lipid oxidation rates than Tween 20- and DTAB-stabilized emulsions, especially at low pH. Lipid oxidation in salmon oil-in-water emulsions was inhibited by EDTA and the iron-specific chelator, apo-transferrin, indicating that oxidation was promoted by iron. Furthermore, Tween 20-stabilized salmon oil emulsions oxidized faster at pH 7.0 than 3.0. An explanation for this oxidation trend may be due to Fe3+ associating more with Tween 20 emulsion droplets at higher pH's due to its lower solubility. The ability of iron to decompose cumene hydroperoxide in emulsions stabilized by SDS (anionic), Tween 20 (nonionic), and DTAB (cationic) was determined. Peroxide decomposition was greater in SDS-stabilized emulsions due to increased iron-peroxide interactions at the emulsion droplet interface. Factors that decrease iron-emulsion droplet interactions including pH, EDTA, and NaCl inhibited Fe2+ promoted decomposition of cumene hydroperoxide in the SDS-stabilized emulsions. Cumene hydroperoxide in Tween 20 was more susceptible to decomposition by iron at pH 7.0 than 3.0.

Polyether surfactants, such as Tween and Brij will accumulate peroxides. Peroxides originating from Tween 20 micelles exhibited changes in peroxide formation and decomposition, the balance of which depended on the concentration and reactivity of iron. In the presence or absence of added iron or copper, peroxides originating from Tween 20 were capable of oxidizing α-tocopherol. Oxidation of α-tocopherol by Fe2+ in Tween 20 micelles was inhibited by EDTA. In conclusion, lipid oxidation rates in emulsions could be lowered by using techniques that decreased the interaction of transition metals at the interfacial region of the droplet.

Indexing (details)

Food science
0359: Food science
Identifier / keyword
Biological sciences; Emulsions; Fish oil; Iron; Lipid oxidation
Characterization of iron-promoted lipid oxidation in emulsions
Roy, Jennifer Lee
Number of pages
Publication year
Degree date
School code
DAI-B 60/05, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
0599329165, 9780599329164
Decker, Eric A.
University of Massachusetts Amherst
University location
United States -- Massachusetts
Source type
Dissertations & Theses
Document type
Dissertation/thesis number
ProQuest document ID
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
Access the complete full text

You can get the full text of this document if it is part of your institution's ProQuest subscription.

Try one of the following:

  • Connect to ProQuest through your library network and search for the document from there.
  • Request the document from your library.
  • Go to the ProQuest login page and enter a ProQuest or My Research username / password.