摘要:

Chlortetracycline had no effect in prolonging the keeping quality of round and eviscerated freshwater fish when stored at 30 °C. However, the effectiveness of the antibiotic in prolonging the storage life of fish fillets stored under identical conditions was demonstrated.

ISSN:0706-652X    

DOI:10.1139/f59-001

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Samples of sea water from eight locations at the surface around the coast of the Atlantic Provinces of Canada have been analyzed for their content of major and minor chemical constituents. The salt water in the Bras d'Or Lakes of Cape Breton Island, N.S., was different from that in the contiguous Atlantic Ocean and showed evidence of much dilution. The seven other samples examined averaged 17.17‰ for chlorinity and 31.03‰ for salinity. These averages are low for open oceanic waters. The average composition of sea water for this area was as follows in grams per kilogram: Na, 9.55; K, 0.34; Ca, 0.37; Mg, 1.15; SO4, 2.36; B as H3BO3, 0.0243. Concentrations of the trace elements in micrograms per litre varied within the following limits: As as As2O3, 1.4 to 2.0; Co, 0.33 to 0.67; Cu, 13 to 22; F, 860 to 1200; I, 6 to 53; Mo, 6.3 to 14.0; PO4, 5 to 69; Si, 44 to 95; Zn, 6.5 to 10.9. Nickel was also present in all samples but vanadium was not detected. The various ratios of the mineral elements, especially to chlorine, have been calculated, and show only slight divergence from those for open ocean water.

ISSN:0706-652X    

DOI:10.1139/f59-002

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Bacteria capable of producing fruity and onion-like odours have been isolated from Atlantic cod and haddock fillets that had developed off-odours of this type. These organisms have been identified as being non-proteolytic strains ofPseudomonas fragi.Compared to other fish-spoiling bacteria, including cultures ofSerratia,Proteus,Achromobacter, and green pigmentedPseudomonas,Ps.fragiis quite sensitive to the bacteriostatic action of antibiotics of the tetracycline group.

ISSN:0706-652X    

DOI:10.1139/f59-003

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The characteristic fruity and onion-like odours produced byPs.fragiare the result of these organisms acting on substrates containing partially hydrolyzed proteins. It has been shown that the immediate protein derivatives from which the bacteria produce the fruity odours are mono-amino monocarboxylic acids. The fruity smelling compounds are probably volatile esters formed after bacterial deamination of these amino acids.Under some conditions these organisms are able to produce various types of sour-onion and garlic-like odours. It has been found that these odours are also produced through the action of the bacteria on amino acids, but are not restricted to the mono-amino monocarboxylic group. Nothing is yet known of the mechanism by which these onion-like odours are formed.Fruity and oniony odours are only two of many different odours produced by the action of these organisms on amino acids. Among others, they are also able to produce odours suggesting cabbage, sour cabbage and rotten vegetables from methionine; cooked egg yolk, and hydrogen sulphide-like odours from cysteine, cystine, and glutathione; and various sour vegetable-like odours from other amino acids.

ISSN:0706-652X    

DOI:10.1139/f59-004

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Ultracentrifuge examination of extracts of post-rigor Atlantic cod muscle showed the actomyosin fraction to consist of one major component, three minor components, and a gel fraction. At ion concentrations above 0.9 the major component dissociates to form two of the minor components.

ISSN:0706-652X    

DOI:10.1139/f59-005

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Lipid hydrolysis with formation of free fatty acids occurs rapidly in frozen cod fillets at +10°F, and slowly at −10°F. In fatty fish the free fatty acid development is slower but still temperature dependent. It appears that when appreciable lipid hydrolysis occurs on storage usually the actomyosin extractability, as well as taste panel scores, decreases. Contrary to most previous results, there was no loss in actomyosin extractability or taste panel acceptability up to a year and a half in the frozen cod at −10°F.

ISSN:0706-652X    

DOI:10.1139/f59-006

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Tropomyosin has been prepared from Atlantic cod muscle dehydrated with ethanol and ether according to Bailey's procedure. Properties measured included electrophoretic mobility, sedimentation constant, solubility as a function of pH, and viscosity. The preparations contained a small amount of nucleic acid not associated with the protein.

ISSN:0706-652X    

DOI:10.1139/f59-007

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The efficiency with which acetone or isopropanol can extract fat, water-solubles, and proteinaceous materials from Atlantic cod muscle depends upon changes in the water content of the solvent. Optimum dilutions for maximum yields of extractives have been determined.

ISSN:0706-652X    

DOI:10.1139/f59-008

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The bias in individual estimates of the natural mortality coefficient derived from the ratio of successive virtual populations is defined algebraically and is shown to be unchanged whether one or more year-classes is considered, if the mortality coefficients are assumed to be constant for all exploitable fish. Limiting and probable values of this bias are shown graphically for a coefficient of fishing mortality ranging from 0 to −2.0 in the year for which the estimate is obtained. These values are drawn for a true natural mortality of −0.2 and −0.4 and for both an increasing and a decreasing fishing effort. Bias in individual estimates of natural mortality is greatest when there are large fluctuations in fishing effort, particularly when fishing mortality is low relative to natural mortality, and it increases with increased natural mortality.A linear regression of a series of virtual population ratios would in general give an intercept value which underestimated the coefficient of natural mortality, and a slope which overestimated the coefficient of fishing mortality, in situations where F has tended to increase and also where it has had no trend (the "steady state" of Table I). Both these errors would be in the opposite direction during a period when there was a decline in fishing effort.

ISSN:0706-652X    

DOI:10.1139/f59-009

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

A specimen ofOncorhynchus gorbuscha552 mm in fork length, taken in the Skeena River fishery in 1956, had scales indicating two years of growth completed and substantial 3rd-year growth.

ISSN:0706-652X    

DOI:10.1139/f59-010

出版商:NRC Research Press    

年代:1959

数据来源: NRC