Maximising the Value of Marine By-Products

Fereidoon Shahidi

• Publisher: Woodhead Publishing
• Year: 2006
• Print ISBN:
  9781845690137
• eBook ISBN:
  9781845692087
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Despite declining stocks, a major portion of the harvest of fish and marine invertebrates is discarded or used for the production of low value fish meal and fish oil. Marine by-products, though, contain valuable protein and lipid fractions as well as vitamins, minerals and other bioactive compounds which are beneficial to human health. Devising strategies for the full utilization of the catch and processing of discards for production of novel products is therefore a matter of importance for both the fishing industry and food processors. Maximising the value of marine by-products provides a complete review of the characterisation, recovery, processing and applications of marine-by products.Part one summarises the physical and chemical properties of marine proteins and lipids and assesses methods for their extraction and recovery. Part two examines the various applications of by-products in the food industry, including health-promoting ingredients such as marine oils and calcium, as well as enzymes, antioxidants, flavourings and pigments. The final part of the book discusses the utilization of marine by-products in diverse areas such as agriculture, medicine and energy production.With its distinguished editor and international team of authors, Maximising the value of marine by-products is an invaluable reference for all those involved in the valorisation of seafood by-products. - Learn how to devise strategies for the full utilisation of the catch - Understand the importance of marine by-products to human health - Explores the use of marine by-products in diverse areas such as agriculture, medicine and energy production

Part I

Marine by-products characterisation, recovery and processing

Outline

Chapter 1: Physical and chemical properties of protein seafood by-products

Chapter 2: Physical and chemical properties of lipid by-products from seafood waste

Chapter 3: On-board handling of marine by-products to prevent microbial spoilage, enzymatic reactions and lipid oxidation

Chapter 4: Recovery of by-products from seafood processing streams

Chapter 5: Increased processed flesh yield by recovery from marine by-products

Chapter 6: Enzymatic methods for marine by-products recovery

Chapter 7: Chemical processing methods for protein recovery from marine by-products and underutilized fish species

1

Physical and chemical properties of protein seafood by-products

T. Rustad, Norwegian University of Science and Technology, Norway

Publisher Summary

It is a challenge to utilize more protein fractions from fish by-products as food ingredients. Many protein-rich marine by-products have a range of dynamic properties and can potentially be used in foods as binders, emulsifiers, and gelling agents. Fish proteins have unique functional properties such as capacity to bind water, lipids, rheological properties, etc. but, due to lack of a suitable purification process to preserve protein functionality, fish protein has been lacking in the rapidly growing protein ingredient and health markets. This chapter discusses the physical and chemical properties of protein seafood by-products. The functional properties of proteins are defined as physical and chemical properties that affect the behavior of proteins in food systems during processing, storage, preparation, and consumption. The sensory properties of foods result from interactions between several functional ingredients. The physical and chemical properties that determine protein functionality include the size and the shape of the proteins, the charge and the distribution of charge and the flexibility as well as the ratio between the hydrophobicity and the hydrophilicity. Handling, processing, and storage of raw materials will all affect the functional properties and it is therefore important to both characterize the functional properties of the raw material and find out how the different processing steps will affect these properties.

1.1 Introduction

Overexploitation of fish resources is a major problem as only 50–60% of the catch is used for human consumption. Globally, more than 91 million tonnes of fish and shellfish are caught each year. Some of the by-products are utilised but huge amounts are wasted. Annual discard from the world fisheries has been estimated to be 25% of the catch. Only a small amount of the by-products is used for human consumption, the rest is used for production of fishmeal, silage and animal feed. A list of valuable components in fish by-products is given in Table 1.1. Fish provides about 14% of the world’s need for animal proteins and 4–5% of the total protein requirement (Venugopal, 1995). The amino acid composition and digestibility of fish proteins is excellent. It is a challenge both to increase the utilisation of the protein fractions from marine by-products and to use more of these valuable proteins as food ingredients.

Table 1.1

Valuable components of fish by-products

Lipids	Proteins	Other components
Oils	Hydrolysates	Nucleic acids
Omega-3: EPA, DHA	Surimi	Calcium
Phospholipids	Thermostable dispersions	Bioactive compounds
Squalen	Peptides, amino acids	Colours
Vitamins	Gelatine, collagen
Cholesterols	Protamines

Use of by-products is not new. In the Nordic countries a lot of the byproducts have been and are still being used for various purposes. For instance fish skin has earlier been used to cover window openings, to make clothes, shoes, carrier packs and sacks. Some fish by-products that are used for human consumption include roe (canned, salted/marinated or as cod roe emulsion), liver (Eastern Europe), cleaned stomach, fried fish milt (a snack) and head products from Iceland (cheeks, tongues, dried heads).

In 2000 a total of 251 000 metric tonnes of by-products were created by the Norwegian cod fisheries alone, of this 114000 tonnes were dumped while 137 000 tonnes were utilised. Only 33 000 tonnes of the by-products were used for human consumption which amounts to about 13% of the total (RUBIN, 2001). The rest is used for production of fishmeal, silage and animal feed. A large part of the by-products that are dumped at sea are made up by heads (Stoknes and Hellevik, 2000). In Norway only about 20% of the cod heads are exploited. Of this 9000 tonnes goes to human consumption, mostly as dried heads to Nigeria. In some fisheries the tongues and cheeks are cut out. The rest is minced and used as feed for fur animals.

Fisheries and fish industries are the single most important industry in Iceland. In 2001 the total catch was around 2 million tonnes, accounting for 62% of the value of exported products and around 48% of the foreign currency earnings that year. Fish meal and oil constitute the bulk of the volume of products from fisheries in Iceland or 63% of total, but their value is far less or only about 14% of the total value of exported seafood products. In 2001, Iceland exported about 45 500 tonnes of by-products with a value of US$73.5 million.

Of a total available UK fish and shellfish resource of approximately 850000 tonnes, only 43% end up as products for human consumption. The rest is categorised as ‘waste’. About 300 000 tonnes of this is produced on shore, whereas the rest is produced at sea (145 000 tonnes discarded fish and 43 000 tonnes processing waste). For cod-fish these numbers can be broken down to 154 000 tonnes on shore and 37 000 tonnes at sea. In the UK the major outlet for this raw material is fishmeal and oil production, only small quantities are used for other purposes (pet food, animal feed, fishing bait, etc.). In some areas of the UK the by-products primarily end up in landfill sites...

Table of contents

• Cover image
• Title page
• Table of Contents
• Related titles
• Copyright
• Contributor contact details
• Preface
• Maximizing the value of marine by-products: an overview
• Part I: Marine by-products characterisation, recovery and processing
• Part II: Food uses of marine by-products
• Part III: Non-food uses of marine by-products
• Index