摘要:

AbstractResponses of maincrop potatoes to N, P and K fertilisers were measured in 119 experiments done by Soil Scientists of the National Agricultural Advisory Service in the years 1955‐62. The experimental sites were spread over 13 soil groups, most of which corresponded to particular soil series.Average crop responses to P and K are given for each soil group. The amount of response was related to soil texture and to content of soluble P or K in the soil. For a given content of soluble P in the soil, crops on loamy sand and sandy loam soils gave a larger response to the first level of P fertiliser (0.5 cwt P2O5per acre) than did those on silty loams, clay loams and clays; but the additional response to the second level of P fertiliser and, consequently to the optimum dressings of P, was greater for crops grown on the heavier‐textured soils. P response was also related to depth of freely drained soil, sites with impeded drainage giving larger responses to P than freely drained sites.The proportion of soils poor in K, crop responses to K and optimum dressings of K fertiliser were all greater for the loamy sands and sandy loams than for the silty loam, clay loam and clay soils.The optimum dressings of N and K for almost all the soil groups were less than the average amounts currently used on maincrop potatoes in Great Britain; however, the seasons seem to have been relatively unfavourable to N and K responses. For P, the average amounts used were less than the optimum for most of the silty loam, clay loam and clay soils but more than the optimum for most soils of lighter text

ISSN:0022-5142    

DOI:10.1002/jsfa.2740180301

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractThe effects of several dehydration processes on chemical compounds which may contribute to apple flavours and histological changes were investigated. It was shown that the effects on chemical compounds and histological changes were minimal by freeze dehydration as compared with other dehydration processes studied. Cryogenic freezing and osmotic dehydration treatments prior to freeze dehydration prevented cellular damage during the freezing step and had little adverse effect on the tissue of freeze dehydrated apple slices.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740180302

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractFurther results are given for changes in wheat being stored for a period of 10 years or more under conditions such as might be used for long‐term commercial storage. The effects of low temperature and low oxygen tension, singly and in combination, on the changes in the chemistry and in the baking and physical characteristics of the doughs occurring during storage are being studied.The present paper reports and discusses the changes that have taken place in grain that has been stored for a total period of eight years under the four conditions of the experimen

ISSN:0022-5142    

DOI:10.1002/jsfa.2740180303

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractTriglycerides were isolated from a number of different tissues obtained from six adult sheep; the tissues including internal fat depots (perinephric and mesenteric), subcutaneous fat depots (rump and chest) and the subcutaneous region of the metatarsal part of the hind limbs and of the pinnae of the ears. The fatty acid composition of these triglycerides was determined by gas‐liquid chromatography and the intramolecular distribution of the acids was studied using pancreatic lipase to remove selectively the fatty acids esterified to the primary alcoholic groups (1‐ and 3‐positions) of the glycerol molecules. Unsaturated fatty acids of thetransconfiguration were estimated by infra‐red absorption analysis.In confirmation of earlier, less detailed, studies it was found that the triglycerides of the internal tissues contained a much higher proportion of saturated fatty acids (particularly stearic acid) than did those of the external tissues. In the most exposed tissues (legs, ears) oleic acid accounted for as much as 60‐70% of the total fatty acids present.Transfatty acid (almost entirely C18mono‐unsaturated) was, like stearic acid, found in greatest concentration in the internal tissue triglycerides.Regardless of their location in the body all the triglycerides examined showed a similar pattern of intramolecular distribution of their major component acids; saturated acids (palmitic acid and stearic acid) were for the most part esterified in the 1‐ and 3‐positions, and oleic acid was found predominantly esterified in the 2‐position.Transunsaturated acid, when present, showed a similar degree of preferential esterification in the 1‐ and 3‐positions to that observed for stearic acid.It was tentatively concluded that long‐chain fatty acids absorbed from the intestine influence primarily the composition of the triglycerides of

ISSN:0022-5142    

DOI:10.1002/jsfa.2740180304

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractAn investigation has been carried out in order to avoid deamination of cytosine residues in the isolation of deoxyribonucleic acid (DNA) using hot alkali. DNA obtained by the method of W. Jones1contains much smaller amounts of uracil residues than that generally available commercially. Attempts to modify the method of Jones to yield a completely undeaminated product and at the same time to maintain the simplicity of this process, were not successful; the products were either deaminated to the same extent or contained much protein. It was found that, during the action of alkali at 100° on highly‐polymerised DNA, cytosine residues were deaminated to uracil residues and free adenine and traces of guanine were liberat

ISSN:0022-5142    

DOI:10.1002/jsfa.2740180305

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractAbout 35 volatile compounds have been detected in canned Malayan pineapple and 18 of these have been identified by the gas chromatographic analysis of headspace vapours using columns containing polyethylene glycol 400, di‐(2‐cyanoethyl) ether and polypropylene glycol. A new method of sampling headspace vapours is described.Peaks in the chromatograms were classified by subtraction with group reagents, namely dimedone, hydroxyammonium chloride and alkaline hydroxyammonium chloride, which removed aldehydes, all carbonyl compounds, and esters and carbonyl compounds respectively. Individual compounds were identified by their relative retentions on three different stationary pha

ISSN:0022-5142    

DOI:10.1002/jsfa.2740180306

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractThe amino acid compositions of glutenins and gliadins from two strong and two weak wheats have been compared. Glutenin appears to have an amino acid analysis generally similar to that of gliadin but there are individual differences. Glutenin possesses much higher proportions of lysine, glycine and tryptophan and somewhat higher proportions of arginine, tyrosine, threonine, (aspartic acid + asparagine), serine and alanine. Gliadin is richer in proline, (glutamic acid + glutamine), cystine, phenylalanine, amide nitrogen and isoleucine. No definite differences were observed in contents of methionine, valine, leucine or histidine. The possible significance of these results in explaining the properties of glutenin and gliadin is discussed, and the results are compared on a diagram with some analyses in the literature. No significant differences in amino acid composition from variety, or from strong wheats as against weak, were observed among glutenins or gliadins. The calculated factor for converting weight of nitrogen to glutenin or gliadin is 5.6. The mean percentage of (glutamic + aspartic) acids in the amide form is 82 for glutenin and 92 for gliadin.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740180307

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractCuring and drying of unshelled groundnuts is difficult when harvesting coincides with the rainy season. Groundnuts on haulms have then a high moisture content and if not cured or dried artificially to a safe moisture level, deteriorate quickly on storage. Work on the comparative merits of sun‐drying and accelerated‐drying has been carried out and the storage behaviour of the respective lots studied using as a control, nuts, not subjected either to sun or accelerated drying. Sun‐dried groundnuts were slightly lower in free fatty acids during the storage period. Accelerated‐dried groundnuts also kept well both in respect of free fatty acids and peroxide value

ISSN:0022-5142    

DOI:10.1002/jsfa.2740180308

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractA new technique is described for the progressive extraction of wheat‐flour proteins using columns. Purified sand is the only diluent used, and even packing is made possible by the use of a vacuum. Good rate of flow, filtration of effluents and reproducibility of results are obtained, and air can be excluded if necessary. Solutions of cysteine, dithiothreitol and amyl thioglycollate in water or 40% isopropanol raise the extractability of protein from wheat flour, under some conditions nearly to a quantitative level. Their action is attributed to the depolymerisation of glutenins by disulphide scission. Heating flour to 114° in a microwave oven causes little change in the extractability of proteins, but treatment with 1‐butanol (to remove lipids) markedly lowers the extractability of proteins, even in the presence of th

ISSN:0022-5142    

DOI:10.1002/jsfa.2740180309

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractOrganochlorine insecticide residues in a wide range of wild birds and their eggs from all over Britain have been determined by gas‐liquid chromatography and paper chromatography. Higher residues were found in predatory species than in omnivorous or herbivorous species. To illustrate the residue pattern in predatory species analytical data for specimens of the Heron, Kestrel and Sparrow‐Hawk have been summarised. The source of the residues and their possible effects upon birds are discus

ISSN:0022-5142    

DOI:10.1002/jsfa.2740180310

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY