Degree Type

Thesis

Date of Award

2009

Degree Name

Master of Science

Department

Food Science and Human Nutrition

First Advisor

Tong Wang

Abstract

Oxidation of tocotrienol enriched corn oil was measured for primary oxidative products, lipid hydroperoxides and quantified by peroxide value (PV). Oxidative Stability Index (OSI) was used to determine the induction period (hrs) by indirect measurement of volatile secondary oxidation products, mainly formic acid. Vitamin E stripped corn oil samples were spiked with individual tocotrienols or tocopherols (collectively, tocols) at concentrations between 100 and 5,000 ppm. A positive relationship was observed between the concentration of all tocols and inhibition of the formation of secondary products. Gamma tocotrienol (γ-T3) provided the most protection, with delta tocopherol (δ-T) and delta tocotrienol (δ-T3) providing similar protection. Alpha tocotrienol (α-T3) and alpha tocopherol (α-T) followed a similar trend but with diminishing capacity at concentrations higher than 700 ppm. The change in mean daily peroxide value increased as α- tocopherol and α- tocotrienol concentrations increased. When compared against the non-spiked, stripped control oil, both α- tocopherol and α- tocotrienol demonstrated better antioxidant effects at lower concentrations and actually promoted oxidation at concentrations at 700 ppm and above. These effects were not observed with the γ- and δ- tocols.

Crude oils from corn kernels, both control and that expressing a homogentisate geranylgeranyl transferase (HGGT) gene, were tested for oxidative stability. No pro-oxidant effects were observed in the modified crude corn oil containing up to 5,000 ppm tocotrienols (6,200 ppm total tocotrienols and tocopherols) when compared to the control crude corn oil containing 300 ppm tocotrienols (1,500 ppm total tocols).

DOI

https://doi.org/10.31274/etd-180810-776

Copyright Owner

David Andrew Dolde

Language

en

Date Available

2012-04-30

File Format

application/pdf

File Size

52 pages

Included in

Nutrition Commons

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