Chemical and Functional Properties of Food Saccharides

16
CONTENTS
© 2004 by CRC Press LLC
Carbohydrates of Animal
Tissues
Tadeusz Kolczak
16.1 Introduction
16.2 Glycogen
16.2.1 Glycogenesis
16.2.2 Glycogenolysis and Glycolysis
16.3 Glucosylaminoglycans
16.3.1 Proteoglycans
16.3.2 Metabolism of Glucosylaminoglycans
16.3.3 Utilization of Glucosylaminoglycans
16.4 Glycoproteins
References
16.1 INTRODUCTION
Carbohydrates constitute quantitatively a much smaller component of the tissue in
animals than they do in plants. They are present, however, in all animal tissues and
tissue fluids as free compounds (D-glucose and glycogen), as components of nucleic
acids, nucleosides, some proteins, and lipids. 1 For instance, D-glucose and its polymer
glycogen, stored in liver and skeletal muscles, are the primary source of energy
for organisms. Pentoses constitute cellular nucleic acids, which are involved in the
transfer of genetic code and protein biosynthesis. Glycoproteins, with their oligosaccharide
components, are essential components of cell membranes. Polymers of
hexosoamines (proteoglycans) occur in connective tissues in which they function as
intracellular cement substances or as lubricants in joint fluids. Conjugated glycolipid
containing D-galactose is essential for the functioning of nerve tissue.
The quality of meat products depends more on carbohydrates, their metabolites,
and compounds with carbohydrate components than on any other organic substances.
The rate and extent of chemical processes in postmortem transformation of muscle
to meat and their effect on its ultimate properties and quality are controlled, to a
great extent, by reactions of carbohydrates. Sensory and inherent mechanical