Okra extracts as emulsifiers for acidic emulsions

K. Alba, V. Kontogiorgos, N. Georgiadis, C. Ritzoulis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Extracts rich in pectins were isolated by aqueous extraction at pH. 4.0 (OE4) and 6.0 (OE6) from okra (Abelmoschus esculentus) pods. They were examined in terms of their composition and emulsion stabilizing capacity in model acidic emulsions (hexadecane-in-water at pH. 3.0). Extracted polysaccharides were assessed using size exclusion chromatography (SEC) and FTIR spectroscopy. The properties and stability of the resulting emulsions were examined by means of droplet size distribution and ζ-potential measurements, viscometry, fluorescence microscopy and protein interface concentration. As emulsifiers, both extracts produce emulsions of initially monomodal size distribution and of similar average droplet size, while ζ-potential was negative for both. The emulsions prepared using OE6 are relatively stable in terms of droplet size distribution and average droplet size after 30. days of storage, while emulsions prepared with OE4 increase in droplet size, in part attributable to Ostwald ripening. Determination of the protein interface coverage Γsuggests that the increased stability of the OE6 emulsions should be attributed to the higher protein load of the interfaces prepared using this extract, resulting to increased rigidity of the interface. Viscosity of emulsions containing OE6 was two times greater than OE4 while aging increases the viscosity of both emulsions. The present work suggests that okra extracts can be strong candidates for emulsification in acidic environments.
Original languageEnglish
Title of host publicationGums and Stabilisers for the Food Industry 17 - The Changing Face of Food Manufacture: The Role of Hydrocolloids
PublisherRoyal Society of Chemistry
Pages238-244
Number of pages7
Publication statusPublished - 2014
Event17th International Gums and Stabilisers for the Food Industry Conference - Glyndwr University, Wrexham, United Kingdom
Duration: 25 Jun 201328 Jun 2013
Conference number: 17

Publication series

NameFood Research International
Number2
Volume54
ISSN (Electronic)0963-9969

Conference

Conference17th International Gums and Stabilisers for the Food Industry Conference
CountryUnited Kingdom
CityWrexham
Period25/06/1328/06/13

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