摘要:

Abstract“Compulsive” exchange takes place between a barium‐soil and magnesium sulphate solution because Ba2+ions are removed from solution by precipitation of barium sulphate. This phenomenon provides a basis for the very convenient routine method for cation‐exchange capacity determination in soils described here. An EDTA titration is used to measure the amount of magnesium exchanged from a standard solution by a Ba‐soil, which enables the cation‐exchange capacity to be calculated. Advantages of the method are its speed and that the sample does not have to be washed exhaustively, so avoiding possible hydrolysis. It compares favourably with standard A.O.A.C. procedure and is much more widely applicable. Soils rich in organic matter, e.g., peats, or with much calcium carbonate, can be handled without

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151201

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractMaize and wheat treated with malathion was stored in sealed jars for 6 months and analysed monthly for malathion and its derivatives. Dimethyl phosphorothiolothionic acid, malathion mono‐acid and malathion di‐acid were identified by thin‐layer chromato‐graphy, but malaoxon and its corresponding derivatives were not detected. The breakdown of malathion under these conditions appears to be hydrolytic rather than oxidative,

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151202

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe effect of storing soils at −20° on their subsequent ability to mineralise nitrogen on incubation differs according to the soil, because significantly more mineral‐N (ammonium‐and nitrate‐N) and nitrate‐N was produced by three of four soils tested. These increases, apparently induced by freezing and thawing, may have been partly related to the moisture and carbon contents of the soils. Samples stored for different periods up to 6–9 months differed little in their rates of mineralisation. Experiments with added ammonium‐N suggested, however, that numbers of nitrifying organisms decreased after 6

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151203

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractLoaves made from gluten and starch alone were inferior in volume and texture to loaves made with the addition of flour solubles. The effect of flour solubles was destroyed by enzymes which degrade polysaccharides but was unaffected by an active protease.Other viscous gums were tested for effectiveness in improving the volume of gluten‐starch loaves. A wide range was effective, but some had no effec

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151204

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractA process for the preparation of spray‐dried infant food containing 26% of protein and 18% of fat is described. The product is based on a blend of coconut protein, groundnut protein isolate, skim milk powder, dextrins and hydrogenated groundnut oil and is fortified with vitamins and minerals. It is light cream in colour and reconstitutes readily in water. Laboratory samples are free fromEscherichia coliand other pathogenic anaerobes and the total plate count is of the order of 15,600/g. When packed in polyethylene bags (100 gauge) and stored in tin containers at 37°, it kept well for 9 months, the losses of vitamins A and C and thiamine at the end of the storage period being 25, 32 and 20%, respective

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151205

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe nutritive value of a spray‐dried infant food described in Part I was studied by growth experiments on albino rats. The growth of albino rats on the infant food diet was 15.3 g. as compared with 13.9 g. for a control milk food of a similar composition. A 3 : I blend of infant food and cane sugar promoted a weekly growth rate of 18.1 g. as compared with 16.1 g. obtained for a similar blend of control milk food and sugar. No significant differences were observed in the contents of liver‐protein and fat but protein and calcium contents of the carcasses of animals receiving infant food were lower than of those receiving milk food. When incorporated at 20% level (providing about 5% of extra protein) in maize‐tapioca diets and at 10% level in rice diets, the food was as effective in promoting growth in rats. However, in the compositions of the liver and carcass there were some significant though inconsistent differences, between the diets on maize‐tapioca and rice. The livers of rats receiving the supplement of infant food or milk food were normal, indicating that both the supplements were effective in correcting the protein deficiency in the diets and in preventing liver damage which occurred in the unsupplemente

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151206

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe internal DDT deposits in the leaves of a barley strain (Rika) which is susceptible to DDT and of one (Proctor) which is resistant, were found to be the same. DDT specifically accumulated to the same extent in both strains.Neither DDT (2.56 × 10−5M) nor DDE (2.75 × 10−5M) inhibited the Hill reaction in either strain. When DDT at approximately 30 p.p.m. was included in a water culture solution, no adverse effect on the root system of either strain was noted; only very slight uptake of DDT into the plant was noted. The susceptible strain when germinated in the presence of DDT is not adversely affected until the 10th day, i.e., when all food reserves are used up. No significant metabolism of DDT by either strain could be observed even when [14C]‐DDT was used.Examination of 19 DDT analogues revealed three structural requirements for toxicity.It is concluded that DDT exerts its toxic effect in Rika by gaining access to a functional lipoprotein in the chloroplast by being able to penetrate the membrane; in Proctor it is adsorbed on the chloroplast but presumably cannot penetrate the chloroplast m

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151207

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe analytical methods used in foliar diagnosis at the Cocoa Research Institute, Tafo, are described; and their accuracy and precision tested by statistical analysis. The variables which might influence the harvesting of a representative leaf sample were studied. The age, size and position of leaf with respect to light and time of day of sampling affected nutrient concentrations of N, P, K, Mg and Ca in the leaves. Sampling of alternate trees of a plot of 100 trees (planted at 8 ft. × 8 ft.) indicated that on the average about 50% and 14% of the tree population should be sampled to show a significant difference of 10% and 20% respectively at P = 0.05.A sampling procedure is recommended

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151208

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe activity of an active polyphenol oxidase which is mainly located in the skin of sultana grapes decreases during ripening, but it is still active at full maturity. It is suggested that the browning of untreated grapes during drying is mainly caused by this enzyme. The dipping process, used to increase the drying rate, prevents browning, but it does not affect the enzyme or its activity directly. The drying rate is increased without a corresponding increase in oxygen uptake of the fruit, so that it is concluded that the enzyme is unspecifically inhibited by rising sugar concentrations, and not by components of the dipping solution. The prevention of browning of drying grapes can be achieved by an increased drying rate without dipping treatment.A mutant “Bruce's Sport” of the grape variety Thompson's seedless, which yields light‐coloured raisins, does not contain an active polyphenol oxidase, but contains similar amounts of ph

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151209

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe residual fats in germinating seeds from four different species did not show any detectable acetyl value by sensitive gravimetric methods. Thein vivohydrolysis of triglycerides in plants hence appears to take place probably by a “quantum” mechanism wherein a triglyceride molecule is split up into fatty acids and glycerol with little or no intermediate liberation of mono‐ and di‐gly

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151210

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY