HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by King, R. L. Search for Related Content PubMed Articles by King, R. L.

Oxidation of Milk Fat Globule Membrane Material. II. Relation of Ascorbic Acid and Membrane Concentrations

Department of Dairy Science, University of Maryland, College Park

ABSTRACT

The rate of development of oxidized flavor in model systems as influenced by the initial concentration of ascorbic acid was measured by the thiobarbituric acid reaction. At constant fat globule membrane material (FGMM) concentration, the rate of lipid oxidation increased with increasing initial concentration of ascorbic acid up to 20–40 mg/liter. Further increases effected inhibition of lipid oxidation in relation to the concentration of ascorbic acid. At constant initial ascorbic acid concentration, the rate of lipid oxidation increased directly with FGMM concentration. The initial reaction rate appears to follow zero-order kinetics over-all. Energy of activation was 11.9 k cal/mole. The rate of ascorbic acid oxidation was proportional to the rate of lipid oxidation. Addition of copper in concentrations < 0.1 ppm inhibited both the rates of lipid and ascorbic acid oxidation. Copper addition > 0.1 ppm increased ascorbic acid oxidation, but lipid oxidation was further inhibited. It is suggested that the lipid oxidative system is activated by association with ascorbic acid and inhibited by products of ascorbic acid oxidation.