Food Biochemistry and Food Processing (2 edition)

BLBS102-c16 BLBS102-Simpson March 21, 2012 10:54 Trim: 276mm X 219mm Printer Name: Yet to Come

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Biochemistry of Processing Meat and Poultry

Fidel Toldra ́

Background Information

Description of the Muscle Enzymes

Muscle Proteases

Neutral Proteinases: Calpains

Lysosomal Proteinases: Cathepsins

Proteasome Complex

Exoproteases: Peptidases

Exoproteases: Aminopeptidases and

Carboxypeptidases

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

References

Abstract:The biochemical changes happening during meat con-

ditioning (aging) were abundantly reported during the 1970s and

1980s. It has been in recent decades that more information has been

available for the biochemical changes in other products such as

cooked, dry-fermented, and dry-cured meats. The processing and

quality of these meat products have been improved based on a better

knowledge of the biochemical mechanisms involved in the genera-

tion of color, flavor, and texture. The endogenous enzyme systems

that play important roles in these processes mainly through prote-

olysis and lipolysis reactions are described in this chapter. Other

biochemical reactions like oxidation, glycolysis, and nucleotides

breakdown are also described.

BACKGROUND INFORMATION

There are a wide variety of meat products that are attractive

to consumers because of their characteristic 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 consumption in the summer.

Curers expanded these products by trying different recipes based

on the use of additives such salt, sugar, pepper, spices, and so

forth, and smoking (Toldr ́a 2002).

Although scientific literature on biochemical changes during

meat conditioning (aging) and in some meat products were abun-

dantly reported during 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 processing and quality of these meat

products prompted research in the last decades on endogenous

enzyme systems that play important roles in these processes,

which has been later demonstrated (Toldra 2007). It is impor- ́

tant to remember that the potential role of a certain enzyme in

a specific observed or reported biochemical change can only

be established if all the following requirements are met (Toldr ́a

1992): (1) the enzyme is present in the skeletal muscle or adi-

pose tissue, (2) the enzyme is able to degrade in vitro the natural

substance (i.e., a protein in the case of a protease, a triacylglyc-

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

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.

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