BLBS102-c10 BLBS102-Simpson March 21, 2012 13:7 Trim: 276mm X 219mm Printer Name: Yet to Come
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Protein Cross-linking in Food – Structure,
Applications, Implications for Health and
Food Safety
Juliet A. Gerrard and Justine R. Cottam
Introduction
Protein Cross-Links in Food
Disulfide Cross-links
Cross-links Derived from Dehydroprotein
Cross-links Derived from Tyrosine
Cross-links Derived from the Maillard Reaction
Age Protein Cross-Links Isolated to Date in Food
Health and food safety aspects of MRPs
Melanoidins
Maillard-Related Cross-Links
Cross-links Formed via Transglutaminase Catalysis
Other Isopeptide Bonds
Manipulating Protein Cross-Linking During Food Processing
Chemical Methods
Enzymatic Methods
Transglutaminase
Future Applications of Protein Cross-Linking
Acknowledgements
ReferencesAbstract:The capacity of proteins to cross-link with each other has
important implications for food quality. Protein cross-linking can
influence food texture and appearance, or permit the incorporation
of useful nutrients such as essential amino acids or essential oils in
foods to accrue crucial benefits. Protein cross-linking in foods may
be achieved by enzymatic means with transglutaminase or with
cross-linking agents like glutaraldehyde. This chapter discusses the
different cross-linking effects and how they may be exploited by
food processor.INTRODUCTION
Protein cross-links play an important role in determining the
functional properties of food proteins. Manipulation of the num-
ber and nature of protein cross-links during food processingoffers a means by which the food industry can manipulate the
functional properties of food, often without damaging the nutri-
tional quality. This chapter updates the chapter in the previous
edition of this book and discusses advances in our understand-
ing of protein cross-linking over the last two decades, as well as
examining current and future applications of this chemistry in
food processing and its implications for health and food safety.
It draws on, and updates, two reviews in this area (Gerrard 2002,
Miller and Gerrard, 2005) in addition to earlier reviews on this
subject (Matheis and Whitaker 1987, Feeney and Whitaker 1988,
Singh 1991).
The elusive relationship between the structure and the func-
tion of proteins presents a particular challenge for the food tech-
nologist. Food proteins are often denatured during processing,
so there is a need to understand the protein both as a biolog-
ical entity with a predetermined function and as a randomly
coiled biopolymer. To understand and manipulate food proteins
requires a knowledge of both protein biochemistry and poly-
mer science. If the protein undergoes chemical reaction during
processing, both the ‘natural’ function of the molecule and the
properties of the denatured polymeric state may be influenced.
One type of chemical reaction that has major consequences for
protein function in either their native or denatured states is pro-
tein cross-linking. It is, therefore, no surprise that protein cross-
linking can have profound effects on the functional properties
of food proteins.
This chapter sets out to define the different types of protein
cross-links that can occur in food, before and after processing,
and the consequences of these cross-links for the functional and
nutritional properties of the foodstuff. Methods that have been
employed to introduce cross-links into food deliberately are then
reviewed, and future prospects for the use of this chemistry
for the manipulation of food during processing are surveyed,
including a consideration of health and food safety aspects.Food Biochemistry and Food Processing, Second Edition. Edited by Benjamin K. Simpson, Leo M.L. Nollet, Fidel Toldr ́a, Soottawat Benjakul, Gopinadhan Paliyath and Y.H. Hui.
©C2012 John Wiley & Sons, Inc. Published 2012 by John Wiley & Sons, Inc.207