摘要:

AbstractThe solution behaviour of amylosic chains has been reviewed in light of the stiffness parameter ρ. The stiffness parameter is reevaluated for three probable conformations of amylose in solution according to Burchard. It is shown that the boat conformations explain the flexibility of amylosic chains which is consistent with their solution behaviour

ISSN:0038-9056    

DOI:10.1002/star.19700220102

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractThe effect of polyhydric and monohydric alcohols, of phenols, of carboxylic acids and their anions, of halide anions, of alkalimetalions and of some other compounds on the gelatination temperature of potato starch granules in aqueous solutions were studied.Polyhydric alcohols and methanol raise the gelatination temperature, whereas ethanol, propanol, butanol, p‐dioxane, carboxylic acids, phenols, urea and hydrogen peroxide cause a decrease in the gelatination temperature. The effect of polyhydric alcohols may be attributed to the lessened tendency of the medium to rupture hydrogen bonds. Carboxylic acids, phenols, urea and hydrogen peroxide may act in a opposite way. The lowering effect of the monohydric alcohols, dioxane, and other non‐polar substances may be due to structural and kinetic alterations of the aqueous medium, induced by the non‐polar groups. At higher concentrations of ethanol, propanol, p‐dioxane, acetic, propionic and butyric acid the gelatination temperature tends to increase. This is to be attributed to the association of solute mo

ISSN:0038-9056    

DOI:10.1002/star.19700220103

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractThe Development of Some Characteristics of Starches extracted from Normal Corn and Amylomaize Grains during their Formation.Within the research work on the evolution of corn grains constituents with different amylose contents, during their development, a study has been carried on the starch content of corn grains, amylose content of starch grains, microscopical and submicroscopical aspects of starch grains and their crystalline organization marked by X rays diffraction.The quantity of starch synthetized for one corn grain is stated as all the more important as the amylose content of grain is lower.For amylomaizes, it is pointed out that the determination of amylose content of starch carried on at 2°C leads to higher values than at 20°C. The difference between the results might be ascribed to the presence of a glucidic fraction reacting as amylose and synthetized in a relatively important proportion at the beginning of corn grain formation, and later on becoming diluted with the other amylaceous components.The increasing stability of amylomaize starches when thermically treated might correlate with their amylose conten

ISSN:0038-9056    

DOI:10.1002/star.19700220104

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractNitratability of three different polymeric dextrans with predominantly α‐1,6‐linked anhydro‐D‐glucopyranose units was studied in different nitrating agents. The degree of substitution (D. S.) increases with increase of the absolute nitric acid/dextran ratio. Due to gelatinization of dextrans in this medium, this nitrating agent is comparatively less effective for dextran nitration than for starch with predominantly α‐1,4‐D‐glycosidic linkages; the latter has great affinity to dissolution in this medium. Nearly complete nitrations (D. S., 2.96) were readily obtained from dextrans by nitration in presence of 25% each of acetic acid and acetic anhydride.In nitric‐sulphuric acids mixtures the nitratability of dextran is mainly a function of acids composition. Gelatinization occurred in mixed acids containing up to 20% H2SO4. Successful nitrations (D. S., ca. 2.6) were always obtained, however, from mixed acids containing 38% or more sulphuric acid, but the use of 62% sulphuric acid is more economic for industry. The sulphate content is greatly dependent on the acids composition and it is, as well, affected by the chemical nature of the corr

ISSN:0038-9056    

DOI:10.1002/star.19700220105

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractDirect Investigations of the Surface of of Fractured Potato Starch Grains.The section‐plane after preparing ultrathin sections as well as the surface of fractures of pieces of potatoes, embedded in Vestopal were studied, using a scanning‐electron‐microscope. The surface of fractures of starch grains demonstrates a smooth circular part outside, the center shows a radial stru

ISSN:0038-9056    

DOI:10.1002/star.19700220106

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractWheat starch granules were subjected to alpha‐amylolysis after which they were examined in the Scanning electron microscope.Much variation exists among starch granules; thus conclusions based on the observation of the precise mode of α‐amylase attack on a few individual granules may not be generally applicable. It has been found, however, that where a groove is present in a granule, α‐amylase attack generally occurs here, complete penetration either occurring exclusively at this feature or accompanying penetration at apparently randomly located sites on the major surfaces.This preliminary investigation of starch granules attacked by amylase has provided new information which augments the results of studies by other microscopical methods. Observation of the detailed structure of the equatorial groove in modified granules is particularly relevant to a better understanding of this feature in starch g

ISSN:0038-9056    

DOI:10.1002/star.19700220107

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractRecent Experiences with Dorr‐Oliver Multicyclones and D‐O DSM Screens in the Potato Starch Industry.Potato starch flowsheets are described i. e. one from 1958, one from 1962 and the most up‐to‐date one (1968) showing a combined D‐O DSM‐Screening system for coarseand fine pulp together and separate Dorr Clone washing systems for optimal refining of coarseand fine granule starch.Tables are given, showing results obtained during recent campaigns. Finally data are disclosed regarding power consumption and w

ISSN:0038-9056    

DOI:10.1002/star.19700220108

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19700220109

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19700220110

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19700220111

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY