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Nutritive Aspects of Fish Oils
CHAPTER 3
Nutritive Aspects of Fish Oils Y. TOYAMA Department of Applied Chemistry, N a g o y a University, Furo-cho, Chikusa-ku, N a g o y a , Japan AND
T. KANEDA Tokai Regional Fisheries Research Laboratory, Tsukishima, Tokyo, Japan
I.
II.
Nutritive Value of Fish Oil Components A. Fish Oil Glycerides B. Highly Unsaturated Acids C. Miscellaneous Edible Oils from Fish Sources A. Hydrogenated Fish Oils B. Polymerized Fish Oils References
149 149 152 157 161 162 163 165
I. Nutritive Value of Fish Oil Components
Owing to the complex nature of fish oils, it appears less advisable to make general statements about their nutritive values. Consideration should always be given to their various constituents, their chemical composition as well as their general and specific properties. In spite of massive research in the field of fish oil chemistry (see Chapters 7 and 8 of Volume I ) , present information is still very scant as to the nutritive implications and certainly too fragmentary to allow even tentative generalizations. The nutritional significance in general of fish lipids was analyzed by Lovern in 1958. It is common knowledge that fish oils contain glycerides and unsaponifiable matter. The latter varies markedly as to amount, depending on the species of fish. This unsaponifiable matter includes various components, but vitamins such as A, D, or E will not be directly considered here. Fish oils as a source of calories, as well as related aspects, will be mainly discussed in this chapter. A.
FISH OIL GLYCERIDES
As a whole, fish glycerides have the same biological value as fats of land animals and vegetable oils. Compared with terrestrial animal fats, aquatic animal oils show a marked complexity in their fatty acid com149
Nutritive Aspects of Fish Oils Y. TOYAMA Department of Applied Chemistry, N a g o y a University, Furo-cho, Chikusa-ku, N a g o y a , Japan AND
T. KANEDA Tokai Regional Fisheries Research Laboratory, Tsukishima, Tokyo, Japan
I.
II.
Nutritive Value of Fish Oil Components A. Fish Oil Glycerides B. Highly Unsaturated Acids C. Miscellaneous Edible Oils from Fish Sources A. Hydrogenated Fish Oils B. Polymerized Fish Oils References
149 149 152 157 161 162 163 165
I. Nutritive Value of Fish Oil Components
Owing to the complex nature of fish oils, it appears less advisable to make general statements about their nutritive values. Consideration should always be given to their various constituents, their chemical composition as well as their general and specific properties. In spite of massive research in the field of fish oil chemistry (see Chapters 7 and 8 of Volume I ) , present information is still very scant as to the nutritive implications and certainly too fragmentary to allow even tentative generalizations. The nutritional significance in general of fish lipids was analyzed by Lovern in 1958. It is common knowledge that fish oils contain glycerides and unsaponifiable matter. The latter varies markedly as to amount, depending on the species of fish. This unsaponifiable matter includes various components, but vitamins such as A, D, or E will not be directly considered here. Fish oils as a source of calories, as well as related aspects, will be mainly discussed in this chapter. A.
FISH OIL GLYCERIDES
As a whole, fish glycerides have the same biological value as fats of land animals and vegetable oils. Compared with terrestrial animal fats, aquatic animal oils show a marked complexity in their fatty acid com149