Fruticola En Colmbia

Advances in Colloid and Interface Science 128–130 (2006) 267 – 272
www.elsevier.com/locate/cis

Review: Mechanism of oil uptake during deep-fat frying and
the surfactant effect-theory and myth
Dina Dana, I. Sam Saguy ⁎
Institute of Biochemistry, Food Science and Nutrition, Faculty of Agricultural, Food and Environmental Quality Sciences,
The Hebrew University of Jerusalem, P.O. Box 12,76100 Rehovot, Israel
Available online 29 December 2006

Abstract
Three mechanisms have been previously proposed to explain the complex process of oil uptake during deep-fat frying. The mechanisms
reviewed are water replacement, cooling-phase effect and surface-active agents. The former mechanism describes mainly oil uptake of relatively
large voids in the fried food created due to waterevaporation. The second mechanism furnishes an explanation for the significant amount of oil
absorbed when the food is removed from the fryer. At this point, product surface characteristics and oil viscosity play paramount roles. Surfaceactive agents’ formation provides only a limited explanation for the increased oil uptake during prolonged frying. Reviewed literature, theory and
new data showcontradicting values and do not support the myth that during extended frying time the surfactants generated reduce the contact
angle and/or the interfacial tension, and consequently, influence oil uptake significantly. Higher oil uptake after extended frying time is probably
related to higher oil viscosity caused by polymerization reactions and oil adherence to the product surface. Further research isneeded for
establishing the interrelationships between surface-active agents’ formation and their effect on fried product oil uptake and quality to resolve this
myth.
© 2006 Elsevier B.V. All rights reserved.
Keywords: Contact angle; Surface-active agents; Viscosity; Interfacial tension

Contents
1.
2.
3.

Introduction . . . . . . . . .
Oil uptake . . . . . . . . .
Oil-uptakemechanism . . .
3.1. Water replacement . .
3.2. Cooling-phase effect.
3.3. Surface-active agents
4. Conclusions. . . . . . . . .
References . . . . . . . . . . . .

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1. Introduction
Frying is a widespread process, as reflected by extensive
sales and a large spectrum of products. The palatability of fried
foods lies in theirunique organoleptic characteristics,
including flavor, texture and appearance. Deep-fat frying is
⁎ Corresponding author. Tel./fax: +972 8 9489019.
E-mail address: ssaguy@agri.huji.ac.il (I.S. Saguy).
0001-8686/$ - see front matter © 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.cis.2006.11.013

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