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Distribution of catechol in emulsions
Author(s) -
Losada Barreiro Sonia,
Bravo Díaz Carlos,
Costa Marlene,
PaivaMartins Fátima
Publication year - 2014
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3196
Subject(s) - chemistry , catechol , partition coefficient , emulsion , aqueous solution , partition (number theory) , oil droplet , chromatography , chemical engineering , organic chemistry , mathematics , combinatorics , engineering
In this work, we have evaluated the effects of emulsifier concentration on the distribution of catechol (1,2‐dihydroxybenzene, CAT) in food‐grade emulsions composed of stripped corn oil, acidic water, and Tween 20. Auxiliary experiments in binary stripped corn oil–water mixtures, in the absence of emulsifier, showed that CAT is both oil and water soluble (partition constant P W O = 0.34). Addition of Tween 20 to prepare kinetically stable emulsions creates an interfacial region, and the distribution of CAT is now described by two partition constants, that between the oil and interfacial region, P O I , and that between the aqueous and interfacial region, P W I . These partition constants were determined in the intact emulsion by employing a kinetic method that exploits the reaction between the hydrophobic 4‐hexadecylbenzenediazonium ions, 16‐ArN 2 + , and CAT. Results show that CAT distributes between the three regions. At emulsifier volume fractions of Φ I = 0.005, CAT is predominantly located (~61%) in the aqueous region, about 26% is in the interfacial region, and only a small fraction (~13%) in the oil region. An increase in emulsifier concentration promotes the incorporation of CAT to the interfacial region up to ~70% at Φ I = 0.037. Results obtained should contribute to a better understanding of the antioxidant efficiency in inhibiting lipid oxidation and to the development of new strategies to prepare healthier and more nutritional foods with longer shelf life. Copyright © 2013 John Wiley & Sons, Ltd.