摘要:

AbstractCommercial high‐amylose corn, ordinary corn and potato starches were fully acetylated by reacting the starches at 123°C for 5 h in fourfold quantities of acetic anhydride to which 11% (w/w starch) of sodium hydroxide catalyst had been added as 50% aqueous solution. Intrinsic viscosities of the starches regenerated from their esters were slightly lower than the values for the corresponding unreacted starches and indicated that only minor degradation hat occurred during acetylation. Amylose obtained by the butanol fractionation of corn starch was also readily acetylated by this procedure. However, commercial potato amylose required removal of the small amount of magnesium sulfate present to achieve both full acetylation (44.8% acetyl) and minimum depolymerization of the star

ISSN:0038-9056    

DOI:10.1002/star.19720240302

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractIn earlier studies since 1961 [1] the author has observed that the A type starch granules of Wheat and other Hordeae show between crossed Nicols in most cases differentiated polarization crosses. In the center of these there is a little high double refracting disk with a small dark polarization cross. In the broader outer zone, which is not so bright, the armes of the small cross are persued much broader and indistinct.A. D. Evers (1971) has shown with the scanning electron microscope that the development of A type starch granules begins with an initial minute spherical granule, which becomes a „nucleus”︁, and which is progressively surrounded in the equatorial plane by a continually enlarging structure which resembles two lips with a furrow between them. When the lips have surrounded the „nucleus”︁ the thickness and diameter of the granule continue to increase in such a way that the furrow becomes shallower and is present in the mature biconvex structure only as a sh

ISSN:0038-9056    

DOI:10.1002/star.19720240303

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractThe kinetics of pyrolysis of amylose, amylose acetate and amylose propionate has been studied using thermogravimetric (TGA) and differential thermal analysis (DTA) in nitrogen atmosphere. Chatterjee, Anderson and Freeman, and Reich methods of analysis have been applied to the TGA and DTA data of these polymers. The Chatterjee method adequately explains the initial stage of pyrolysis of the polymers, while Anderson and Freeman, and Reich methods yield high activation energy in contrast to the experimental evidence.Thermal analysis showed that the thermal stability of amylose increases when it is substituted. Amylose has been found to decompose before melting, while the esters melt before decomposition. The melting temperature of the esters decreased with increased size of the pendent groups.

ISSN:0038-9056    

DOI:10.1002/star.19720240304

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractExperiments for Improvement of the Filtration of Starch Syrup. Possibilities for the improvement of starch syrup filtration according to these experimental results do not primarily depend on the type of plant which is used but on composition and the amount of suspended matter in syrups to be filtered. It was found that products of discontinually operating reactors are inhomogeneous. Even in products of 40 DE unsoluted starch could be traced. Laboratory tests have shown that a change of filtration rate of starch hydrolysates in the range below 46 DE is greater than in the range over 46 DE.A connection was found to exist between the degree of degradation and the electro‐kinetic properties. Moreover, it was found that the amount of filtration inhibiting matter cannot be reduced to a level below 5 vol.‐%. For the removal of these gel‐like components a gel separation unit for continual operation was constructed with a maximum capacity of 10 000 l/h. In practical application the apparatus removed 94% of the suspended matter extracted from the upper, middle and lower regions of the tank. Thus, the output of the filter station increased to 30 from 20 tons pe

ISSN:0038-9056    

DOI:10.1002/star.19720240305

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19720240306

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19720240307

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19720240309

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19720240313

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19720240301

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY