摘要:

AbstractStarch granules were prepared from 14 indica rice grains which were collected from various places of Asia and had the amylose content of 28% and over by a blue value method. The starches were high‐ and medium‐amylose types by the enzymatic and chromatographic method. However, none of them belonged to the type of high amylose mutants which were induced by the chemical mutagen treatment of a japonica rice cultivar: Kinmaze and possessed similar characteristics of endosperm starch to that of the amylose‐extender (ae) mutant of maize (Zea may

ISSN:0038-9056    

DOI:10.1002/star.19920440602

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractAnnealing and heat/moisture‐treatment both cause a physical modification of starches without any gelatinization, or any other damage of the starch granules with respect to size, shape or birefringence only via a controlled application of heat/moisture. Since with respect to the application properties (gelatinization. viscosity etc.) almost idential modifications can be obtained with both treatments, there was no exact differentiation between the two treatments types.By application of both treatments as well as a combination of both to potato starch it could be demonstrated that both treatments cause completely different alterations of the internal granule structure. From the interpretation of the Brabender viscosity, the sorption isotherm, the DSC‐curves and the X‐ray diagrams it could be confirmed that a heat/moisture‐treatment always means a structure alteration from a B‐type in the direction of an A‐type structure, whereas within annealing processes the property alteration have to be explained by a modification of the binding forces between the crystallites and the amorp

ISSN:0038-9056    

DOI:10.1002/star.19920440603

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractEine repräsentative Probe von einer klinisch verwendeten Hydroxyethylstärke wurde mittels semipräparativer HPGPC in enge Molekulargewichtsfraktionen im Bereich von ca. 3 000 bis 800 000 D aufgetrennt. Ausgangsprobe und ausgewählte Einzelfraktionen wurden durch gaschromatographische Methylierungsanalyse in bezug auf die Substitutionsgrade MS und DS charakterisiert, wobei diese nach Substitutionsposition C2, C3 und C6 der Anhydroglucosen und deren glycosidische Bindungsart α‐1, α‐1,4 bzw. α‐1,4,6 unterschieden wer‐den. Ebenfalls ermittelt wurde die Polydispersität in bezug auf die Verzweigung.Weiterhin werden die durch Multidetektions‐HPSEC ermittelten Kenngrößen zur Molekulargewichtsverteilung und die Mark‐Houwink‐Parameter angegeben. Die Daten zeigen insgesamt eine weitgehende Homogenität der Ausgangsprobe in bezug auf die gemessenen Parameter. Ihre klinische

ISSN:0038-9056    

DOI:10.1002/star.19920440604

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA series of starch graft copolymers were prepared from commercial cornstarch products and vinyl monomers and were evaluated as adhesives in pigmented paper coatings. Hypochlorite oxidized (HO), acid modified (AM), and hydroxyethlated acid modified (HEAM) starches were reacted separately with acrylamide (AAm), acrylic acid (AAc), and acrilonitrile (AN) using ceric ammonium nitrate as the polymerization initiator to yield copolymers containing 2–45% synthetic polymer. Pigmented coating mixtures with 6–14 parts co‐polymer/100 parts clay and 40–50% total solids were prepared and applied on one side of the paper stock using a hand‐drawn doctor blade. Viscosities, adhesive strength, and wet‐rub resistance of the coating adhesives and mixtures were determined. Adhesive strength of starch graft polyacrylamide (S‐g‐PAAm) copolymers containing as little as 12% PAAm was considerably superior to the commercial starches as paper coating adhesives. Adhesive strength of S‐g‐PAAc copolymers was similar to that of the HO and HEAM commercial starches, whereas adhesive strength of the S‐g‐PAN copolymers was poor. Copolymers that were prepared from the HO starch were slightly superior to those prepared from the AM and HEAM starches. Wet‐rub resistance of the pigmented copolymer coatings was not improved over that of the coatings containin

ISSN:0038-9056    

DOI:10.1002/star.19920440605

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA column flow‐through enzyme enthalpymeter was used for the determination of maltose, starch and glucos

ISSN:0038-9056    

DOI:10.1002/star.19920440606

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA new alkalophilic Bacillus. which produced exceptionally high activity of cyclodextrin glycosyltransferase, was isolated from soil. This strain of Bacillus was identified as Bacillus lentus. The enzyme was purified and characterized. It was found that optimum pH and temperature for cyclodextrin forming activity were 6.5–8.5 and 45–55°C. Thermal stability of the enzyme was remarkably increased by the addition of calcium ions. The maximum conversion of starch to cyclodextrin by the enzyme was 65%. The cyclodextrins formed after 24 h of enzymatic reaction consisted of α‐. β‐ and ‐y‐cyclodextrins in proportion

ISSN:0038-9056    

DOI:10.1002/star.19920440607

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractBacillus macerans CGTase recognizes the terminal 6 glucose units of the non‐reducing end of α‐(1→4)‐glucans. Analysis of the chain‐length distributions produced by the action of CGTase on well‐defined maltodextrins gave information on the enzyme's specifity in regard of the size of the transferred glucanosyl‐moiety.It was found that in the presence of α‐cyclodextrin, maltohexaosyl‐groups could be highly specifically coupled to an acceptor like maltose. The product, maltooctaose, appeared in a yield of 45 % molar amount. The affinity for hexaosylresidues was explored by using homodisperse substrates from glucose to maltotriadecaose. HPTLC‐analysis of the product patterns in early states of CGTase catalyzed reactions revealed that the yield of the primary coupling product decreased with increasing DP. This was due to the effect, that disproportion was more rapid on higher oligomers. The intermolecular transfer of glucanosylgroups was also found to be size‐dependent, inasmuch as the relative CGTase transfer activity decreased gradually from maltohpxaosyl‐ to glucosylresidues. In an investigation of the enzymic degradation of maltodextrins maltononaose gave

ISSN:0038-9056    

DOI:10.1002/star.19920440608

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19920440609

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19920440610

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19920440611

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY