Food Biochemistry and Food Processing (2 edition)

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Seafood Enzymes

M. K. Nielsen and H. H. Nielsen

Introduction

Cold Adaptation of Enzymes

Effects of Pressure on Enzyme Reactions

Osmotic Adaptation of Enzymes

Enzymatic Reactions in the Energy Metabolism of Seafood

Postmortem Generation of ATP

Postmortem Degradation of Nucleotides

Enzymatic Degradation of Trimethylamine-N-Oxide

The Trimethylamine-N-Oxide Reductase Reaction

The Trimethylamine-N-Oxide Aldolase Reaction

Postmortem Proteolysis in Fresh Fish

Proteases in Fish Muscle

Matrix Metalloproteinases

Cathepsins

Calpains

20S Proteasome

Heat-Stable Alkaline Proteinases

Postmortem Hydrolysis of Lipids in Seafood during Frozen

andColdStorage

Endogenous Enzymatic Reactions during the Processing of

Seafood

Salting of Fish

Ripening of Salt-Cured Fish

Production of Fish Sauce and Fish Paste

Production of Surimi

Technological Applications of Enzymes from Seafood

Improved Processing of Roe

Production of Fish Silage

Deskinning and Descaling of Fish

Improved Production of Fish Sauce

Seafood Enzymes Used in Biotechnology

Potential Applications of Seafood Enzymes in the Dairy

Industry

References

INTRODUCTION

“Freshness” serves as a basic parameter of quality to a greater

extent in seafood than in muscle foods of other types. The atten-

tion directed at the freshness of seafood and seafood products

is appropriate since certain changes in seafood occur soon after

capture and slaughter, often leading to an initial loss in prime

quality. Such changes are not necessarily related to microbial

spoilage, but may be due to the activity of endogenous enzymes.

However, not all postmortem endogenous enzyme activities in

seafood lead to a loss in quality; many autolytic changes are

important for obtaining the desired texture and taste.

Despite the biological differences between aquatic and

terrestrial animals, the biochemical reactions of most animals

are identical and are catalyzed by homologous enzymes; only

few reactions are unique for certain species. Few reactions

are catalyzed by analog enzymes that differ in structure and

evolutionary origin. The aquatic habitat can be extreme in var-

ious respects including temperature, hydrostatic pressure, and

osmotic pressure, compared with the environment of terrestrial

animals. These all conditions have thermodynamic implications

and can affect the kinetics and stability of marine enzymes. Also,

because of the large biological diversity of marine animals and

such seasonally determined factors as spawning and the avail-

ability of food, seafood species can differ markedly in enzyme

activity.

Seafood is a gastronomic term that in principle includes all

edible aquatic organisms. In this chapter, it is mainly the “clas-

sical” seafood groups—fish, shellfish, and molluscs—that are

dealt with. Muscle enzymes are mostly considered, since muscle

is the organ of which most seafood products primarily consist.

Various other types of seafood enzymes, such as those used in

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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