Temperature and emulsifier concentration effects on gallic acid distribution in a model food emulsion

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Sonia Losada Barreiro (Author) Other; Veronica Sanchez Paz (Author) Other; Carlos Bravo Diaz (Author) Other; Fatima Paiva Martins (Author) FCUP; Laurence S Romsted (Author) Other

Journal

Title: Journal of Colloid and Interface Science

Vol. 370

Pages: 73-79

ISSN: 0021-9797

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 37 Citations

Scopus - 37 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-002-C3B

DOI: 10.1016/j.jcis.2011.12.057

Abstract (EN): We determined the effects of emulsifier concentration and temperature on the distribution of gallic acid (GA) in a food-grade emulsion composed of 1:9 vol:vol stripped corn oil, acidic water and Tween 20. The distribution of GA can be defined by the partition constant between the aqueous and the interfacial regions, P-W(l), which was determined by using a kinetic method and the pseudophase kinetic model. Once P-W(l), is known, determining the distribution of GA is straightforward. Our results show that at least 40% of the total GA is located in the interfacial region of the emulsion at 0.005 volume fraction of Tween 20, and this percentage increases to ca. 85% of the total GA at 0.04 volume fraction of Tween 20. The variation of Pwl with the temperature was used to estimate the thermodynamic parameters for the GA transfer from the aqueous to the interfacial region of the emulsion and the activation parameters for the reaction between 16-ArN2+ and GA in the interfacial region. The free energy of transfer from the aqueous to the interfacial region, Delta G(r)(0,W-1), is negative, the enthalpy of transfer is small and negative, but the entropy of transfer is large and positive. Our results demonstrate that the partitioning of GA in acidic emulsions between aqueous and interfacial regions depends primarily on droplet concentration and is only slightly dependent on temperature.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7