ISSN:0022-5142    

DOI:10.1002/jsfa.2740020102

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe reaction of oxygen at atmospheric pressure with dispersed palm‐kernel bag fat has been studied in the range of temperature 50 to 160°c., but principally at 80°c. and with the fat dispersed on glass surfaces, although the reaction with fat‐impregnated jute has also been studied comparatively. The relationships between oxygen consumption, product formation, total pressure change and heat evolution throughout the reaction have been established and the effects of the specific surface of the fat and the pressure of the oxygen on the reaction velocity have been studied. It appears that the oxygen initially attacks the linoleate present more rapidly than the oleate (which is in greater concentration); the linoleate consequently becomes exhausted first and the reaction rate is modified. The heat of initial reaction is about 59 kg.‐cal./mole. Observations on the formation of peroxide and the disappearance of double bonds during the reaction are discussed in the light of the modern views of Hilditch, Farmer and others on the mechanism of oxidation of unsaturat

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020103

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractOn the basis of previously measured rates, rate‐temperature coefficient and heat of the reaction between oxygen and palm‐kernel fat, the steady‐state temperature distribution in uniform columns of palm kernels due to atmospheric oxidation is determined theoretically using a uni‐dimensional model. Temperature rise may be controlled by three factors; (i) conduction loss, (ii) oxygen deficiency and (iii) convection loss. In practice (i) and (ii) or (i) and (iii) usually operate together; however, they may be considered separately in order to define the lengths of column, external temperatures and ventilation rates at which the column is certainly safe from spontaneous ignition; but the margin of safety cannot be determined by this simplified

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020104

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractA study has been made of the pectin‐demethylating enzyme system in apple tissue and the level of activity compared with that in some other fruits. The apple varieties tested show considerable differences in their pectase content. The enzyme shows a maximum activity at pH 6–6: over the pH range of the fruit the activity is much lower, but the enzyme can still produce appreciable effects. Methods for the extraction and concentration of the enzyme are described. The concentrated enzyme preparations are readily inactivated by normal pasteurizing temperatures (68–70°c.), but in juices the enzyme shows a much greater stability. The significance of these findings is discussed in relation to the production of apple juice and

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020105

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractModifications of the Fiske‐Subbarow method are described by which susceptibility to interference by silicate, arsenate, and certain acids and salts was reduced. In view of the possibility that some soils may contain considerable amounts of extractable arsenate and ferric iron, a method for eliminating interference by these two ions, by reduction with metabisulphite, is described. By this procedure, arsenate and ferric iron up to 20 p.p.m. As2O5and 80 p.p.m. Fe had no effects on the determination.The applicability of the modified technique to the determination of phosphate in soil extracts and in plant ashes is examine

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020106

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe present communication draws attention to the commercial significance of an adequate supply of riboflavin in the diet of the breeding hen. The results of an experiment carried out on a commercial breeding farm are reported, in which the basal ration contained 10% of herring meal. The replacement of half the herring meal by dried liver meal is shown to increase hatchability by 16·5%, and reduce the incidence of the specific riboflavin deficiency symptom of ‘clubbed’ down in dead embryos from 5·9 to 0·8%. These results are discussed in relation to recent experiments on factors, other than riboflavin, found to be essential for hatchability. Reference is made to the riboflavin supplements used in commercial breeders' rations available in Northern Ireland at the presen

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020107

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740020101

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY