摘要:

An inexpensive and convenient source of cadmium resonance radiation (λ 3261) of high intensity has been developed. This should make possible more extended studies of cadmium photosensitized reactions. Some preliminary results on the reaction between hydrogen and ethylene are reported.

ISSN:1923-4287    

DOI:10.1139/cjr38b-043

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

The seeds ofConringia orientalis, which contain a bitter principle, were crushed, freed from fat, and steeped in water. The chloroform extract of the aqueous liquor yielded a crystalline substance which was identified as 2-mercapto-5,5-dimethyl-oxazoline (I). It tastes bitter to some persons but is tasteless to others. The suggestion is made that the seeds contain β-methyl allyl isothiocyanate in the form of a glycoside, and that this substance is converted to (I) during the treatment described above.

ISSN:1923-4287    

DOI:10.1139/cjr38b-044

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

The preparation of rennet casein has been studied on both a laboratory and plant scale, and the effect of the various factors in procedure on the quality of the casein produced is discussed. The details of preparation for a product of excellent quality are given. A simple heat resistance test showing the presence of impurities has been developed. The plasticity of a number of caseins has been measured by a direct method in a laboratory extruder, under pressure ranging up to 77,000 lb. per sq. in.; the maximum viscosity measured directly in this study was about one billion, seven hundred million poises. The flow-pressure curves obtained show no tendency towards a yield point, but show varying degrees of structural viscosity and may be fairly well represented by the relationF = kPn, whereFis the flow,Pis the pressure,nandkare constants. Decrease in pH of the casein, decrease in ash, and increase in lactose content all lower the viscosity of plastic casein. Small increases in water content decrease the viscosity greatly. Up to 80 °C. the temperature of drying has no appreciable effect on the viscosity. Moistening of casein plastic is discussed, as is also the distribution of water and vapor equilibria. Plastic casein is shown to exhibit streamline flow in extrusion, and plasticization is therefore more difficult to accomplish.

ISSN:1923-4287    

DOI:10.1139/cjr38b-045

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

An accurate and reliable method for the estimation of tryptophane is described. It is based on the glyoxylic acid reaction, and involves the use of the Evelyn photoelectric colorimeter. The technique makes it possible to ascertain readily whether the color being measured is due only to tryptophane.The method has been applied to casein, of which, if necessary, only 25 mg. is required. The tryptophane determination is readily accomplished on a solution obtained by dissolving the casein in 10 or 20% sodium hydroxide or 5% formic acid by heating for a few minutes. With respect to alkali hydrolysis of casein under pressure, tryptophane is unstable in the sodium hydroxide hydrolysis, but is very stable in the baryta hydrolysis. The age and source of the casein are shown to be factors causing variations in the tryptophane content of different samples of casein, a variability which has been observed by a few previous workers.

ISSN:1923-4287    

DOI:10.1139/cjr38b-046

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

The tannin content of the barks of several Eastern Canadian conifers has been determined by standard methods in an attempt to assess their value as sources of tanning extracts.A more intensive study has been made of the extractable materials of white spruce bark. The chemical reactions of the extract from this bark show that the tannins therein are typical examples of the catechol or condensed group. Comparison of the ratio of tannin to non-tannins and the buffer index of this extract with the corresponding values for several commercial extracts indicates that the spruce extract would probably be fairly astringent. The titration curves of various fractions of the extract show some indications of the character of the non-tannin constituents.

ISSN:1923-4287    

DOI:10.1139/cjr38b-047

出版商:NRC Research Press    

年代:1938

数据来源: NRC