Food Biochemistry and Food Processing

14

Biochemistry of Processing

Meat and Poultry

F. Toldrá

315

Background Information
Description of the Muscle Enzymes
Muscle Proteases
Neutral Proteinases: Calpains
Lysosomal Proteinases: Cathepsins
Proteasome Complex
Exoproteases: Peptidases
Exoproteases: Aminopeptidases
Lipolytic Enzymes
Muscle Lipases
Adipose Tissue Lipases
Muscle Oxidative and Antioxidative Enzymes
Oxidative Enzymes
Antioxidative Enzymes
Proteolysis
Proteolysis in Aged Meat and Cooked Meat Products
Proteolysis in Fermented Meats
Proteolysis in Dry-Cured Ham
Nucleotide Breakdown
Glycolysis
Lipolysis
Lipolysis in Aged Meat and Cooked Meat Products
Lipolysis in Fermented Meats
Lipolysis in Dry-Cured Ham
Oxidative Reactions
Oxidation to Volatile Compounds
Antioxidants
Glossary
References

BACKGROUND INFORMATION

There are a wide variety of meat products that are
attractive to consumers because of their characteris-
tic color, flavor, and texture. This perception varies

depending on local traditions and heritage. Most of

these products have been produced for many years

or even centuries based on traditional practices. For

instance, cured meat products reached America with

settlers. Pork was cured in New England for con-

sumption in the summer. Curers expanded these

products by trying different recipes based on the use

of additives such as salt, sugar, pepper, spices, and

so forth, and smoking (Toldrá 2002).

Although scientific literature on biochemical

changes during meat conditioning (ageing) and in

some meat products were abundantly reported dur-

ing the 1970s and 1980s, little information was

available on the origin of the biochemical changes in

other products such as cooked, dry-fermented, and

dry-cured meats. The need to improve the process-

ing and quality of these meat products prompted

research in the last decades on endogenous enzyme

systems that play important roles in these processes,

as has been later demonstrated (Flores and Toldrá

1993). It is important to remember that the potential

role of a certain enzyme in a specific observed

or reported biochemical change can only be estab-

lished if all the following requirements are met

(Toldrá 1992): (1) the enzyme is present in the skel-

etal muscle or adipose tissue, (2) the enzyme is able

to degrade in vitro the natural substance (i.e., a pro-

tein in the case of a protease, a tri-acylglycerol in the

case of a lipase, etc.), (3) the enzyme and substrate

are located closely enough in the real meat product

for an effective interaction, and (4) the enzyme

exhibits enough stability during processing for the

changes to be developed.

Food Biochemistry and Food Processing

Edited by Y. H. Hui

Copyright © 2006 by Blackwell Publishing