Changes in free amino acids and protein denaturation of fish muscle during frozen storage

The effect of storage at subzero temperatures (-5°C, -12°C, and -20°C) on hake ( Merluccius merluccius L.) muscle free-amino acid fraction was evaluated. A significant increase in free aspartic acid, serine, threonine, arginine, β-alanine, tyrosine, methionine, valine, phenylalanine, isoleucine, leucine, and lysine was found at -5°C, whereas at -12°C, a significant decrease in free glutamic acid, glycine, methyl-histidine, β-alanine, taurine, alanine, and leucine was the most noticeable. No changes in the free amino acid fraction were observed at -20°C. Activity of different kind of enzymes, aminopeptidases, aminoacid deaminases, and decarboxylases might be involved in the changes observed at -5°C and -12°C.

Download Full-text

Rainbow trout (Salmo irideus) produced in Finland VI. Free amino acid composition of refrigerated and frozen rainbow trout

Agricultural and Food Science ◽

10.23986/afsci.71698 ◽

1968 ◽

Vol 40 (2) ◽

pp. 49-53

Author(s):

Ritva-Liisa Sihvola ◽

Jorma J. Laine ◽

Fritz P. Niinivaara

Keyword(s):

Amino Acids ◽

Rainbow Trout ◽

Free Amino Acids ◽

Free Amino ◽

Control Sample ◽

Frozen Storage ◽

Refrigerated Storage ◽

Free Amino Acid Composition ◽

Steady Decrease ◽

Frozen Fish

Changes in the amounts of free amino acids in rainbow trout during refrigerated storage in ice at + 4 . . + 6°C and in frozen storage at –18°C were investigated. The control sample was prepared directly from the killed, bleeded, and gutted fish. The results indicated that the total amounts of free aimino acids decreased in the refrigerated and in the frozen fish. These decreases depended mostly upon the steady decrease of the three quantitatively largest components, namely histidine, tryptophane, and glycine. Histidine formed 36.1 per cent, tryptophane 25.0 per cent, and glycine 15.1 per cent of the total amount of free amino acids in the control sample. In connection with many other amino acids a decrease in their amounts was noted during storage. Changes appearing in refrigerated fish were more distinct than in frozen fish.

Download Full-text

Consequence of Free Amino Acids Generated from Decomposing Fish Muscle

NIPPON SUISAN GAKKAISHI ◽

10.2331/suisan.16.12_10 ◽

1951 ◽

Vol 16 (12) ◽

pp. 10-16 ◽

Cited By ~ 10

Author(s):

Keishi AMANO ◽

Masamichi BITO

Keyword(s):

Amino Acids ◽

Free Amino Acids ◽

Free Amino ◽

Fish Muscle

Download Full-text

The Effect of Sodium Chloride on Proteolysis and on the Fate of Amino Acids Present in the Muscle of Codfish (Gadus callarias)

Journal of the Fisheries Research Board of Canada ◽

10.1139/f59-053 ◽

1959 ◽

Vol 16 (5) ◽

pp. 747-754

Author(s):

E. Bilinski ◽

H. Fougère

Keyword(s):

Amino Acids ◽

Sodium Chloride ◽

Free Amino Acids ◽

Free Amino ◽

Muscle Protein ◽

Chloride Content ◽

Fish Muscle

The rate of proteolysis and the deamination of free amino acids in cod muscle treated with 4, 8, 12 and 16% sodium chloride varies with the sodium chloride content and temperature. Proteolysis of the fish muscle protein is completely inhibited at concentrations of 16 and 12% sodium chloride. Trimethylamine formation is inhibited by 16% sodium chloride for at least 15 days. Both inhibitions take place at either 15 or 25 °C. In salted muscle deamination can occur in the absence of trimethylamine formation. The reaction appears to be hardly influenced by salt. Indole formation is completely inhibited by 8% salt at either 15 or 25 °C.

Download Full-text