摘要:

AbstractThe main fish‐by‐products industry deals with the production of protein feeding‐stuffs and oil from the processing of offal and from fish unsalable for human food. According to whether the raw material is rich or poor in fat, the industry has developed along somewhat different lines.Two recent developmental trends are (a) the introduction of pneumatic (air‐lift) driers having relatively low drying temperatures and very short drying times, with high capacity in relation to size of unit, and (b) the increasing interest in alternative products to conventional fish meal. These are peptized products in which the protein has been largely converted into water‐soluble fragments by acid treatment, or by ensiling the fish with a fermentable carbo‐hydrate (e.g. molasses) and a lactic‐acid‐producing organism. The efficient processing of oily raw material is particularly handicapped by alternating gluts and scarcities of fish, and some methods of storage of raw material are being studied including preservation by addition of alkali, formaldehyde and sodium nitrite or by preservation of a half‐processed commodity such as press‐cake. The seasonal nature of certain fisheries and the migratory habits of the fish, e.g. herrings, have led to many proposals for floating oil and meal factories. The economics of this are far from simple, but development along these lines is in progress in certain areas. Processing of oily material usually involves the expression of about half the total water along with the oil. In some countries, e.g. the U.S.A., the aqueous fluid is concentrated and marketed as a special product, ‘condensed fish solubles’, but the present trend in Europe at least is to return the material in some form to the final meal.Certain otherwise highly efficient types of drier, e.g. the flame drier, have in the past been operated without any attempt to deodorize the large volumes of effluent vapour. A modern development is the designing and increasing use of water‐scrubbing plant for driers of this type. However, the introduction of pneumatic (air‐lift) driers, with enormously increased amounts of effluent air, has brought with it a new problem if deodorization is found to be as necessary a

ISSN:0022-5142    

DOI:10.1002/jsfa.2740060501

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740060502

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractThe chemical fate of methyl bromide absorbed by wheat under the conditions of fumigation has been studied. Whole‐wheat flour was exposed to14C‐labelled methyl bromide. The fat, starch, gluten, and water‐soluble fractions were prepared from the exposed flour and their14C‐content assayed. The gluten or protein fraction was responsible for some 80% of the decomposition of the absorbed fumigant. By measuring the14C of the volatile products obtained on treating the gluten with sodium hydroxide or hydriodic acid under different conditions, it was shown that the decomposition of methyl bromide in gluten was due almost entirely to methylation with the formation of 50% of N‐methyl derivatives, 30% of dimethyl sulphonium derivatives, and of 20% of methoxyl and thiomethoxyl derivatives in about equal proportions. Similar results were obtained when gluten alone was exposed to the labelled fumigant. The production of free methanol in the flour by hydrolysis of the absorbed fumigant was about 10% or less. The rate of spontaneous decomposition of the dimethyl sulphonium compounds formed as a result of fumigation was estimated by using wheat which had been grown on35S‐labell

ISSN:0022-5142    

DOI:10.1002/jsfa.2740060503

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractThe principal reaction between14C‐labelled methyl bromide and the nitrogen‐containing groups of wheat protein has been shown, by combined radioactive tracer‐chromatographic techniques, to be with the histidine residue. Three methylated histidines are present in the hydriodic acid hydrolysate of the protein that has been exposed to methyl bromide, and these have been identified as I‐N‐methylhistidine, 3‐N‐methylhistidine and I:3‐N‐dimethylhistidine. The amount of reaction occurring under typical fumigation conditions is so small that the loss of the semi‐essential amino‐acid, his

ISSN:0022-5142    

DOI:10.1002/jsfa.2740060504

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractThe major products of the chemical reactions between methyl bromide and the constituents of wheat under the conditions of fumigation have been characterized or identified. Their rate of absorption by an adult human consuming fumigated flour products has been estimated. The likely nature of the effective end‐products of human digestion has been considered and is believed to be represented by the compounds, methanol, methylglucoses, S‐methylcysteine, methyl methionine sulphonium salts, andN‐methyl derivatives of histidine and lysine. These appear to be compounds which have been fed experimentally to mammals at concentrations very much larger than those likely to obtain in fumigated wheat. In some cases their metabolismin vivohas also been studied. On the basis of all the available data an appraisal has been made of the toxicological and nutritional significance of consuming fumigated flour products. There is no evidence that the principal fumigant decomposition products are toxic or that their formation would be associated with any significant reduction in essential food constit

ISSN:0022-5142    

DOI:10.1002/jsfa.2740060505

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractMethods are given for determining individual tocopherols in natural oils and food‐stuffs. These methods consist of either a single‐dimensional separation on zinc carbonate‐impregnated paper, or this separation in conjunction with a second‐dimensional partition separation on paraffin‐coated paper. Chromatographic runs are short and rapid and can be made without preliminary removal of carotenoids and moderate amounts of vitamin A or sterols. Over 98% recoveries are obtained with pure tocopherols. The presence of the recently described 5‐methyltocol in wheat products has been confirmed, and, in addition, using two‐dimensional methods, a substance has been isolated from some cereal grains, which appears to be a n

ISSN:0022-5142    

DOI:10.1002/jsfa.2740060506

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractA method is described for the measurement of the amount of expressible fluid in whole fish fillets. The optimum conditions of operation have been worked out with fresh cod, and it is proposed to use the method for studying the changes in the expressible fluid of frozen cod during cold storage.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740060507

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

摘要:

AbstractDeoxypentosenucleic acid (DNA) was determined in the expressible fluid of cod fillets after various treatments. Both size of fillet and time of storage in ice affected the valuesobtained, so standardization of these factors was considered essential to the study of cell damage by means of DNA measurements. It was concluded that the cell breakdownoccurring in fish kept for many days in ice was caused by bacterial action, not autolysis. The expressible fluid itself was found to consist mainly of intercellular fluid, plus a little plasmaexuding from the cut ends of the cells. The DNA appeared to be in true solution, although probably aggregated to some extent.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740060508

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740060509

出版商:John Wiley&Sons, Ltd    

年代:1955

数据来源: WILEY