摘要:

AbstractThe ageing of beef muscle set inrigor mortiswhile restrained at twice its resting, excised length has been examined. Ageing leads to opening of gaps between theAandIbands of the sarcomere. With the shrinkage of both bands during cooking, the gaps become the major feature of the sarcomere and develop within the tenderising time‐scale. As such they represent the most distinct structural change yet encountered to explain the phenomenon of ageing. A possible reconciling of the contradictory views of ageing—splitting at theA–Ijunctions and decay ofZlines—is di

ISSN:0022-5142    

DOI:10.1002/jsfa.2740270402

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractA series of meat meals was prepared from the one type of offal material, sheep stomachs, by batch dry rendering in a model cooker. The meals, designated normal cook (NC), overcooked (OC), rapidly cooked (RC), normal cook with added glucose (GC) and spoilt offal cook (SC), were evaluated as protein supplements by chick growth tests in rations based on wheat and skim milk powder. A control ration (CR) and one incorporating a commercial meat and bone meal (MR), were also included for comparison. No significant differences in weight gain were evident within replicate batches or between treatments NC, GC, OC and RC. Feed conversion ratio (FCR) did not differ significantly within replicate batches NC, OC and RC. A low weight gain and high FCR was given by SC. Weight gain did not vary significantly with feed intake.A significantly higher weight gain and lower FCR was given by CR whilst the lowest weight gain and highest FCR were given by MR, whose results were comparable only with meal from spoilt offal. Available lysine values (ALV) did not show significant decrease in the OC batches, but were lower in the GC batches. These results show that the nutritional value of meat meal is not adversely affected by varying the time of cooking from 1 to 2 1/4 h, by severe overprocessing or by addition of glucose, but that gross spoilage will decrease the nutritive value.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740270403

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractElectrophoretic patterns of protein extracts obtained with different procedures from the BP‐yeast product named Toprina (aCandida lipolyticastrain grown on n‐alkanes) have been compared with protein electrophoretic patterns of a number of different microbial species. The gel electrophoretic pattern of the 0.15MNaCl extract from Toprina was specific enough to allow an easy differentiation of Toprina from the other microorganisms tested.To detect and assay Toprina in blends with animal feeds, an immune serum containing antibodies reacting specifically with Toprina has been prepared by immunising rabbits with an antigen preparation extracted from Toprina with 0.15MNaCl and precipitated by salting out the extract at 4.0M(NH4)2SO4. Three main antibodies reacting with Toprina antigens have been found in the anti‐Toprina immune serum, but only one was specific of Toprina. The resistance of the Toprina antigens to peptic digestion and their behaviour on extraction, electrophoresis and gel filtration suggest that they might be acidic polysaccharide in nature.Immunodiffusion analyses with the anti‐Toprina immune serum of extracts obtained with 0.15MNaCl from very heterogeneous animal feeds added with different amounts of Toprina, allowed the detection of a Toprina amount as low as 2.5%. An accurate assay of Toprina was achieved by submitting the feed extract to radial immunodiffusion with the anti‐Toprina imm

ISSN:0022-5142    

DOI:10.1002/jsfa.2740270404

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractFive toxigenic fungi were grown in the presence of pure cultures of a number of different bacteria. Alterations in the gaseous environment resulting from bacterial growth produced changes in the growth, sporulation and toxin production of the fungi. Different fungi varied in their response to any one bacterium, and different bacteria produced a variety of responses from each individual fungus. The growth, sporulation and toxin production of most fungi were normally inhibited by the presence of bacteria; in a few cases toxin production was stimulated. Toxin production was able to proceed in the absence of sporulation.The implications of bacterium–fungus interactions in certain environments are considere

ISSN:0022-5142    

DOI:10.1002/jsfa.2740270405

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe ESCA (Electron Spectroscopy for Chemical Analysis) technique has been evaluated as an analytical screening method for the determination of protein content and quality of grain meals of some legumes and cereals. To this end the grain meals of a number of different species were analysed for total nitrogen, meals of varieties of cowpea (Vigna unguiculata) were examined for sulpho‐amino acid content, and the levels of basic amino acid in meals of some maize and barley varieties were measured by this technique; some amino acids, polyamino acids and pure proteins were also examined as standards.The results obtained for 15 grain meals by the ESCA technique, expressed as the ratio of the intensity of the N1sphotoelectron signal to that of the C1ssignal, were compared with %N as determined by a semi‐automated micro‐Kjeldahl method, and the correlation coefficient between the results from these two methods wasr= 0.98. The binding energies of S2pelectrons were determined for some amino acids and proteins, and the amino acid sulphur was differentiated from oxidised sulphur. The N1s/S2pintensity ratios for four pure proteins correlated very well with the calculated stoichiometric N/S ratios (r= 0.999). The N1s/S2pintensity ratios were also determined for seven cowpea varieties and the correlation coefficient between these values and the ratios N/Saa, measured by chemical methods, wasr= 0.77.The N1sphotoelectron peaks of some varieties of barley and maize meals showed a pronounced shoulder on the high binding energy side. On deconvolution into two components the main peak was assigned to nitrogen in the peptide bond and the smaller peak was assigned to the protonated nitrogen on the side chains of the basic amino acid res

ISSN:0022-5142    

DOI:10.1002/jsfa.2740270406

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractSpecific activities and isoenzyme multiplicities of glutamic dehydrogenase, esterase, peroxidase, acid phosphatase, acid and neutral invertases were determined in a diploid, a triploid and a tetraploid sugar beet variety. The different ploidy status was accompanied by variations in the level of activity of glutamic dehydrogenase, peroxidase and invertase. Polyploidy induced a number of isoenzymes higher for peroxidase and lower for esterase, acid phosphatase and glutamic dehydrogenase. Specific isoenzyme bands characterised the invertase of the triploid variety.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740270407

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractButanediol is first oxidised to acetoin by butane‐2,3‐diol dehydrogenase from a strain ofSarcina, in the presence of NAD+and an excess amount of 2,6‐dichloro‐phenol‐indophenol at an alkaline pH. Then the acetoin formed is reduced back to butane‐2,3‐diol by the same enzyme in an acidic condition, and NADH thereby oxidised is measured spectrophotometrically. Direct measurement of NADH formation in the first reaction, oxidation of butane‐2,3‐diol, has not yet been successful. Colorimetric measurement of the reduction of 2,6‐dichlorophenol‐indophenol was also unsuccessful. Ethanol in sample solutions should have been removed by evaporation before the enzymatic oxidation. Presence of acetoin caused no difficulty in the oxidation of butane‐2,3‐diol, but made it necessary to correct the measured values for the original acetoin contents. The isomers of butane‐2,3‐diol present in wines have been reported to beD(‐) and meso, on both of which the butane‐2,3‐diol dehydrogenase fromSarcinaappears to be able to act. The butane‐2,3‐diol contents of some Japanese commercial wines were determined by this enzymatic method. Concent

ISSN:0022-5142    

DOI:10.1002/jsfa.2740270408

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractDough was baked in a closed container from which the volatiles were swept with a stream of nitrogen. Carbon dioxide was determined colorimetrically by absorption in an alkaline indicator solution contained in a special cell, in which the flow of gases caused rapid circulation of the absorbent. Graphs of carbon dioxide release against time in oven were sigmoid in form, showing induction periods averaging 4.5 min for mechanically developed (CBP) doughs mixed with fat, and 2.3 min without fat. Analysis of the variance of induction periods and of loaf volumes showed that, in each case, the factor “fatversusno fat” was highly significant. Induction periods were highly correlated with loaf volumes. These results show that loaf volumes are considerably influenced by changes in the permeability of doughs to carbon dioxide at the start of baking. The possibility was considered that carbon dioxide release may occur at a definite transition temperature which is affected by the addition of

ISSN:0022-5142    

DOI:10.1002/jsfa.2740270409

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractOver 90% of the sulpher in some acid surface soils derived from different parent materials in north‐east Scotland was in organic combination. N:S ratios in the majority of the soils fell within the narrow limits of 6.0–7.5, and showed less variation than C:S ratios. Organic sulphur was poorly correlated with organic phosphorus, and high correlations with categories of soluble aluminium and iron seemed to reflect similar relationships between these elements and the whole organic matter. A group of calcareous soils derived from shelly sand deposits contained a lower proportion of organic sulphur. An average 64% of organic sulphur in the acid soils occurred as organic sulphate, compared with only 23% in the calcareous soils. Organic sulphate was less well correlated with carbon and nitrogen than was total organic sulphur. Total carbon‐bonded sulphur was best determined as the difference between total organic sulphur and organic sulphate, because direct measurement by Raney‐nickel reduction underestimated the amount present in most of the soils, due to the presence of chemically unreactive compounds. Good correlations between the reactive carbon‐bonded sulphur and carbon, nitrogen and organic sulphur, suggested that a well‐defined group of compounds was being measured. There were no consistent effects of drainage conditions on organic sulphur contents, or on the amounts and proportions of organic sulphur present as sulphate or in carbon‐bonded form. The freely drained soils derived from basic igneous drift, however, contained more organic sulphur than poorly drained samples, but this is attributed to differences in the organic matter content.Several features of the results indicated that organic sulphur, unlike organic phosphorus, was predominantly an integral part of the soil o

ISSN:0022-5142    

DOI:10.1002/jsfa.2740270410

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractPhosphate‐extractable inorganic sulphate contents of freely drained acid surface soils representing four contrasting soil series in north‐east Scotland ranged from 13 to 60 mg S/kg soil. Of this an average of 59% was adsorbed under the conditions of extraction used. The soils were therefore well supplied with available sulphate and there are no known cases of deficiency in the area. Average group contents of adsorbed sulphate were closely related to the abilities of the soils to adsorb added sulpphate, and unlike phosphate retention, sulphate sorption seemed to depend more on active iron than alumin

ISSN:0022-5142    

DOI:10.1002/jsfa.2740270411

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY