Comparison of Chemical and Enzymatic Interesterification of Fully Hydrogenated Soybean Oil
and Walnut Oil to Produce a Fat Base with Adequate Nutritional and Physical Characteristics

Mariel Farfán, Alfredo Álvarez, Alan Gárate and Pedro Bouchon*

Pontificia Universidad Católica de Chile, Department of Chemical and Bioprocess Engineering, Vicuña Mackenna 4860,
6904411 Santiago, Chile



Article history:
Received August 11, 2014
Accepted March 23, 2015



Key words:
chemical interesterification, enzymatic interesterification, triacylglycerol, hydrogenated soybean oil, walnut oil, solid fat content




Summary:

The optimal physical, chemical and nutritional properties of natural lipids depend on the structure and composition of triacylglycerols. However, they are not always mutually compatible. Lipid modification is a good way to give them specific functionalities, increase their oxidative stability, or improve their nutritional value. As such, chemical and enzymatic interesterification may be used to modify them and produce structured lipids. In accordance, the aim of this study is to compare chemical and enzymatic interesterification of binary blends of fully hydrogenated soybean oil and walnut oil, using sodium methoxide or Lipozyme TL IM, respectively, to produce a fat base with adequate nutritional and physical characteristics. Three different mass ratios of fully hydrogenated soybean oil and walnut oil blends (20:80, 40:60 and 60:40) were interesterified and evaluated. Total interesterification was determined by the stabilization of the solid fat content. Chemical reaction of the 20:80 blend was completed in 10 min and of the 40:60 and 60:40 blends in 15 min. Enzymatically interesterified blends were stabilized in 120 min at all of the mass ratios. Complete interesterification significantly reduced the solid fat content of the blends at any composition. Chemical and enzymatically interesterified fully hydrogenated blend of soybean and walnut oil at mass ratio of 40:60 showed the plastic curve of an all-purpose-type shortening rich in polyunsaturated fatty acids, with a high linolenic acid (C18:3n3) content and with zero trans-fatty acids.




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