The uptake of dissolved oxygen by flour suspensions

Cross, Stanley A. R (1964) The uptake of dissolved oxygen by flour suspensions. PhD thesis, University of Glasgow.

Abstract

The economic significance of wheat in human diet is largely attributable to the complex relationship which exists between its protein and lipid constituents. The technological properties of wheat flour are dependent on the susceptibility of these constituents to mild oxidation. The resulting reactions are of a complex nature but an evaluation of these reactions is a precursor to a more effective utilisation of this important crop as an article of diet. The purpose of this study was to undertake an exploratory investigation into the uptake of dissolved oxygen by wheat flour suspensions. For this purpose flour suspensions were prepared by mixing a fixed quantity of flour and air equilibrated potassium chloride solution. An aliquot of the suspension was taken for study, and the uptake of dissolved oxygen was followed using a polarographic method. The electrodes were a rotating platinum microelectrode, which served as a cathode, and a saturated calomel electrode as anode. The potential applied to the cathode was regulated so that the current recorded on a sensitive ammeter was proportional to the concentration of oxygen in the suspension. Readings of oxygen concentration were taken at fixed intervals over the experimental period. The results indicated that flour takes up oxygen rapidly when wotted. The amount taken up is influenced by commercial oxidative treatments and by the removal of flour lipids. The addition of extracted lipids and linoleic acid increased the uptake of defatted flour. A high level of an antioxidant (NDGA) did not inhibit the uptake mechanism. Sulphydryl blocking agents accelerated the uptake, but did not Influence the overall amount of oxygen taken up by the flour. The addition of reduced glutathione increased the uptake of oxygen in the suspension. Impact milling did not affect the uptake, but differences were noted in the uptake of air classified high and low protein fractions. There was some evidence to suggest that the uptake process was pH sensitive. The results are discussed and related to the theories and findings of other workers.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: J Hawthorn
• Keywords: Food science
• Date of Award: 1964
• Depositing User: Enlighten Team
• Unique ID: glathesis:1964-73309
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 14 Jun 2019 08:56
• URI: https://theses.gla.ac.uk/id/eprint/73309