摘要:

AbstractThis paper is dedicated to Mr. Ernst Hees, Editor of „Die Stärke”︁ from 1958 until December, 1973, as a token of the esteem with which we regard his work in this capacity. We thank him for his efforts, which have so successfully helped to advance the subject of starch chemistry in all its diverse aspects.The techniques of (i) semi‐micro, differential, potentiometric iodine titration of starch with iodine, and (ii) colorimetric assay of the starch‐iodine complex in solution have been compared as analytical tools for the measurement of the amylose‐content of starches. Although the colorimetric method may be calibrated to give comparable results to the potentiometric assay, the former technique is not applicable to maize starches of high amy

ISSN:0038-9056    

DOI:10.1002/star.19740260302

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractMaltosaccharides of degree of polymerisation (DP) 6‐22 have been isolated in a chromatographically pure form, and their iodine staining properties studied under standard conditions. In the range DP 6 to DP 13, there is a logarithmic increase in the intensity of absorption of the iodine complexes; thereafter the relationship is almost linear. A plot of the reciprocals of wavelength of maximum absorption and DP indicates that there are three separate linear sections corresponding to DP 6–11, 12–18 and 18–22. Ammonium sulphate causes an increase in the intensity of absorption and wavelength of maximum absorption in al

ISSN:0038-9056    

DOI:10.1002/star.19740260303

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractObservations on Viscosity Properties of Low‐Substituted Starch Acetates. It was shown that with low‐substituted starches dispersibility in water increases with increasing content of acetyl groups and increasing temperature. This fact becomes evident in lower temperatures at the beginning of pasting and at maximum of „viscosity”︁‐graph. This has confirmed and extended earlier observations. Viscosity of starch acetate pastes is lower in cold as well as in hot state as that of native starch paste. Viscosity decreases down to an acetyl content of 2.36% and it changes only unnoticeably above that point. The decreasing gel forming ability can be expressed by the ratio of paste viscosities in cold and hot state.The rotation viscosimeter Rheotest proved well applicable for studies of viscosity and rheological properties of starch and of low‐substit

ISSN:0038-9056    

DOI:10.1002/star.19740260304

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractDamaged starch granules are produced during flour milling. Such material absorbs more water and is more susceptible to enzymic degradation than unmodified starch. In the present study, X‐ray diffraction measurements were used in an attempt to give a physical explanation of this phenomenon. It is proposed that the effect of milling may be partly attributed to the conversion of starch into a more amorphous for

ISSN:0038-9056    

DOI:10.1002/star.19740260305

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractIrradiated starch was more retrograded than the unirradiated samples. The amylose fractions were increased on the expence of the amylopectin fractions of starch under the influence of gamma rays.Oxidation of starch with periodate ions was enhanced by gamma irradiation as indicated by the formation of greater amounts of formic acid in the irradiated samples. This result indicated that destruction in amylopectin had occured and formed small branched fragments.The decrease in intrinsic viscosity due to radiation, showed a straight line relation, when plotted versus irradiation doses, with a slope of 5.2 × 10−7. This indicates that a specific slope could be obtained which characterized gamma ray doses on wheat flo

ISSN:0038-9056    

DOI:10.1002/star.19740260306

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractA unified method for glucoamylase activity GA determination in microbial material is presented and proposed. The method based on the enzyme action on a 2% soluble starch solution, 30 min 30°C at pH 4.5, and successive determination of the produced glucose by means of glucose oxidase‐peroxidase reagent. The suggested method is simple and facilitates serial analysis. The reproducibility of the assay is very good; the standard deviation from the mean is ± 2%. α‐Amylase present in the tested preparations in the amount up to 0.1 SKB units per 1 ml has no influence on the result of determination. The unit of glucoamylase activity (GA) has been defined as the amount of enzyme, which, in described conditions, will liberate 1 μmol of glucose from starch in the course of one

ISSN:0038-9056    

DOI:10.1002/star.19740260307

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19740260308

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19740260309

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19740260310

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19740260312

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY