摘要:

A sensitive accurate colorimetric method for trimethylamine determination is presented, based on the extraction with toluene of an alkaline sample containing 0.002 to 0.02 mg. trimethylamine nitrogen, and the formation of the yellow coloured picrate by mixing with a picric acid reagent. The application of the method in fishery products and effects of interfering substances have been investigated.

ISSN:0706-652X    

DOI:10.1139/f42-042

出版商:NRC Research Press    

年代:1945

数据来源: NRC

摘要:

Relatively large amounts of nonvolatile higher amines are formed during proteolysis of fish muscle by bacteria. This follows closely the formation of trimethylamine. Fresh fish contain 0.2 mg. nitrogen per 100 g, muscle as trimethylamine and about 0.1 mg. nitrogen per 100 g. as dimethylamine. Trichloracetic acid and formaldehyde solutions completely extracted trimethylamine from fish and satisfactory recovery of added trimethylamine was obtained.

ISSN:0706-652X    

DOI:10.1139/f42-043

出版商:NRC Research Press    

年代:1945

数据来源: NRC

摘要:

Ammonium hydroxide and glycogen have little effect on the formation of trimethylamine from trimethylamine oxide by washed cells of bacteria isolated from fish. Indole, skatole and hydrogen sulphide partially inhibit the enzyme. Partial inhibition can also be effected with cyanide and azide. The necessity in this system of a hydrogen carrier other than the dehydrogenase activating the oxidizable substrate is suggested.

ISSN:0706-652X    

DOI:10.1139/f42-044

出版商:NRC Research Press    

年代:1945

数据来源: NRC

摘要:

The experimental drying of cut samples and of whole salt fish under various air conditions shows that the optimum air velocity is 100 to 125 cm. per second, air temperature 26 °C, and relative humidity 45 to 55 per cent. High drying potentials inhibit drying owing to the formation of an impervious salt-protein crust on the surface of the fish.The skin surface of the fish dries about 50 to 75 per cent as fast as the split surface. Under the recommended air conditions medium size salt codfish are dried from 130 per cent to 75 per cent, dry basis, moisture in about 40 hours.

ISSN:0706-652X    

DOI:10.1139/f42-045

出版商:NRC Research Press    

年代:1945

数据来源: NRC

摘要:

Counts of gill rakers and pyloric caeca on pink salmon (Oncorhynchus gorbuscha) from different rivers in British Columbia overlap in range to such an extent that it would be impossible with any degree of accuracy to assign isolated individuals from an ocean population to a distinct "breeding group" on the basis of these characters. While the comparison of the averages of each character demonstrates significant differences between separate rivers in the same year in some cases, in others no such difference is noticeable. The averages for the characters do not consistently show differences between populations of two succeeding years which are known to be distinct, e.g. those of 1940 and 1941.

ISSN:0706-652X    

DOI:10.1139/f42-046

出版商:NRC Research Press    

年代:1945

数据来源: NRC

摘要:

Some salmon (Salmo salar) parr in a stream descend from the spawning areas, particularly during freshets, to populate lower waters, such as lakes and fresh or brackish parts of estuaries, although killed by full sea water. Thence they ascend and populate available streams variable distances, depending upon conditions such as falls.

ISSN:0706-652X    

DOI:10.1139/f42-047

出版商:NRC Research Press    

年代:1945

数据来源: NRC