摘要:

AbstractStarch samples from different botanical species show few unifying features in either structure or function: for example both the amylose/amylopectin ratio and the amylopectin chain length are found to vary extensively with botanic source. We have applied a detailed analysis to data obtained from small angle X‐ray scattering (SAXS) of a variety of different starches which has shown the existence of a constant structural periodicity. This finding suggests the possibility of a general mechanism governing the way starch is laid down in different specie

ISSN:0038-9056    

DOI:10.1002/star.19930451202

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

Abstractβ‐Limit dextrins were isolated from wrinkled pea starch, fractionated into different sizes, and their molecular weight distribution analysed by gel chromatography. A minor part of the dextrins had high molecular weight and long chains typical for amylose. The major part of the dextrins had low molecular weight and possessed unit chains of the same types as was found in the amylopectin of smooth pea starch. However, the proportion of long chains was significantly higher. The hydrolysis of wrinkled pea starch with α‐amylase was fast and reflected the large content of amylose, whereas the hydrolysis of the β‐limit dextrin was slow. The intermediate dextrin products obtained from the latter had similar molecular weights as those produced from other amylopectins, which indicated that it was build up of clusters of branchings. Structure models that show the mode of interconnection of the clusters in the intermediate material are s

ISSN:0038-9056    

DOI:10.1002/star.19930451203

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractHydrolysis of starch of various origin, liquefied with bacterial α‐amylase to DE 13.5 and then saccharified only with glucoamylase and simultaneously with pullulanase to DE 97–98, was investigated. It was found that the hydrolysis of wheat starch was delayed in relation to the hydrolysis of potato and maize starch, particularly in the first period of saccharification. The delay decreased with time but at the end of the saccharification it was still 24 h. The carbohydrate composition of wheat starch hydrolyzates differed from the hydrolyzates of potato‐ and maize starch in a smaller content of glucose and lower oligosaccharides (G1‐G4) and a greater content of higher oligosaccharides and dextrins (G5‐Gn). This, among other things, could have an influence on higher viscosity of solutions of wheat starch hydrolyzates in relation to respective hydrolyzates of potato and ma

ISSN:0038-9056    

DOI:10.1002/star.19930451204

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractCassava and maize starch were irradiated with an ultraviolet beam of light (337.8 nm) obtained fromBlumlienflat plate transmission line transversely excited atmospheric pressure nitrogen gas laser. Irradiation was carried out on solid starch with and without addition of either zinc, magnesium or titanium oxide.

ISSN:0038-9056    

DOI:10.1002/star.19930451205

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractSweet potato starch (SPS) with 20 or 25% moisture was heated and then fused at 150°C for 15 min under pressurization at 30–500 Kg/cm2. At the same time, the heated SPS melt was extruded through a capillary tube under specified pressure in order to give shearing force. Thus, intact SPS, heated SPS and heated sheared SPS specimen were prepared and examined. The heated and heated sheared SPS did not contain any pyrolysis products because their spectrum profiles were the same as that of intact SPS. By heating and shearing, the intact SPS molecule was depolymerized into small molecules including a few amount of glucose. This finding was revealed by means of molecular weight estimation by viscometry and by gel filtration. The shearing toward SPS melt markedly stimulated the depolymerization while the effect of only heating on depolymerization of SPS was modulate in comparison with heated shearing. Water solubilities of intact SPS, heated SPS and heated sheared SPS with 20% moisture were 0.07, 3.5 and 51.5% respectively, and also the degrees of gelatinization of 1.8% for intact starch increased markedly to 29% for heated SPS and 80–95% (depending on the pressure at extrusion) for heated sheared

ISSN:0038-9056    

DOI:10.1002/star.19930451206

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractEndosperm starch granules prepared from rice, barley, wheat, foxtail‐and proso‐millets were analyzed by Differential Scanning Calorimetry (DSC) and the relationship between melting temperature and enthalpy for starch gelatinization was discussed. Peak temperature for gelatinization (Tp) ranged from 57 to 80°C and enthalpy from 6.4 to 15.6 J/g. Starch from rice, barley, foxtail‐ and proso‐millets which has a waxy phenotype, has shown a correlation between Tp and enthalpy, while that of wheat

ISSN:0038-9056    

DOI:10.1002/star.19930451207

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractEs wurden Untersuchungen zum Einsatz von Cyclodextrin‐Glucosyl‐ Transferase beim enzymatischen Entschlichten von stärkegeschlichtetem Baumwollgewebe durchgeführt. Das verwendete Enzym soll beim Stärkeabbau in Lösung selektiv β‐Cyclodextrin bilden. Wie die vorliegenden Experimente zeigen, ist die CGTase in der Lage, Stärke nicht nur in Lösung, sondern auch auf einem textilen Träger abzubauen. Unter den gegebenen Randbedingungen katalysiert das Enzym die Bildung von α‐Cyclodextrin. Um eine gegenüber α‐Cyclodextrin verstärkte Anreicherung von β‐Cyclodextrin zu erreichen, ist eine genaue Analyse des Prozesses unter Variation und Optimierung der Rand

ISSN:0038-9056    

DOI:10.1002/star.19930451208

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effects of liquid‐starch ratio, concentration of sulphuric acid, and glacial acetic acid on the degree of substitution of acetylated cassava starch were investigated. The optimum liquid starch ratio was 2.5. The degree of substitution increased rapidly with sulphuric acid concentration up to 0.36m at a liquor‐starch ratio of 2.5. The optimum concentration of glacial acetic acid at liquor‐starch ratio of 2.5 and 0.64m sulphuric acid was 13.9m with a reaction efficiency of 88%. The acetylated cassava starch was more soluble than the native cassava s

ISSN:0038-9056    

DOI:10.1002/star.19930451209

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractHydroxyethyl starch is currently finding increasing use as a basis material for plasma volume expanders. In clinical applications it is desirable to have a precise knowledge of the steric and chemical structure, as these affect the pharmacokinetics and pharmacology.Characterization involved the determination of the mean molar masses and distribution functions of various hydroxyethyl starches, with molar masses ranging from 40,000 g/mol to 200,000 g/mol and degrees of substitution from 0.38 to 0.64, by means of size exclusion chromatography followed by double detection (MALLS/RI). Hydrodynamic data (Staudinger indices, Huggins constants and equivalent diameters) were determined by viscometric means.The chemical structure of the hydroxyethyl starches were clarified by {1H}‐13C NMR spectroscopy. Signal assignment for the {1H}‐13C NMR spectra made it possible to carry out an absolute determination of the molar, mean and partial degrees of substitution and the degree of branching. The partial degrees of substitution of the carbon atom C‐2 was found to constitute between 60 and 80% of the total degree of substitution. This value is significantly larger than the partial degrees of substitution at the atoms C‐3 and C‐6, which were found to contribute up to approximately 10% and 20% respectively of the total degree of substitution. Degrees of branching ranging from 3.1% to 5.5% were

ISSN:0038-9056    

DOI:10.1002/star.19930451210

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractAmylose oxidized with nitrogen dioxide, having D.O. by (C=O) 0.38 and by (COOH) 0.94 was converted into its oxime, which after reduction with sodium and isopropyl alcohol yielded (1→4)‐2‐amino‐2‐deoxy‐α‐glucopyranuronan with D.S. by (NH2) 0.30 and by (COONa) 0.85. After acetylation and O‐deacetylation (1→4)‐2‐acetamido‐2‐deoxy‐α‐d‐glucopyranuronan with D.S. by (NHCOCH3) 0.28

ISSN:0038-9056    

DOI:10.1002/star.19930451211

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY