135

 

6

 

Physical Properties 
of Fats and Oils

 

Amanda J. Wright and Alejandro G. Marangoni

 

CONTENTS

 

6.1

Introduction .................................................................................................. 135

6.2

The Physical Properties of Lipids ............................................................... 136
6.2.1

The Effects of Composition............................................................. 136

6.2.2

Lipid Crystallization ........................................................................ 137

6.2.3

The Phase Behavior of Lipids ......................................................... 141

6.2.4

Fat Crystal Polytypism and Polymorphism..................................... 143

6.2.5

Fat Crystal Networks ....................................................................... 146

6.2.6

Rheological Properties ..................................................................... 147
6.2.6.1

Small Deformation Testing............................................... 147

6.2.6.2

Large Deformation Testing............................................... 148

6.3

Modifying the Physical Properties of Lipids .............................................. 150
6.3.1

Changes Through Breeding, Feeding, 
and Genetic Alterations.................................................................... 150
6.3.1.1

Hydrogenation of Fats and Oils ....................................... 150

6.3.1.2

Interesterification of Fats and Oils ................................... 151

6.3.1.3

Fractionation of Fats and Oils.......................................... 151

6.3.1.4

Blending of Fats and Oils
and Combining Technologies ........................................... 152

6.3.2

Changes Related to Processing of Fats and Oils ............................ 152

6.4

Conclusions .................................................................................................. 153

References.............................................................................................................. 153

 

6.1 INTRODUCTION

 

Understanding the physical properties of lipids is critical to the formulation and
manipulation of fats, oils, and fat-structured food products. Rheological properties,
and ultimately texture, are closely related to the structures of underlying fat crystal
networks (FCNs) in foods. Figure 6.1 shows the hierarchy of parameters that deter-
mine the physical properties of lipids and lipid-based materials. Composition and
processing parameters determine the crystalline structure and rheological properties
of FCNs. Differences at the nano- and microstructural levels in fats translate into

 

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