摘要:

AbstractIn this paper the viscosity increase of the starch paste during gelatinization is examined. Upon heating, raw starch granules gelatinize and the paste viscosity of the starch adhesive increases dramatically. Bonding develops further through the dehydration of the gelatinized starch by the board. Bond setting of carrier‐type (mixture of dissolved and raw) starch on paperboard in the corrugated board operation is thought to result from a combination of thermal gelatinization and dehydration by the boar

ISSN:0038-9056    

DOI:10.1002/star.19890410802

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractDie physikalisch‐chemisch modifizierten Stärken, sogenannte „lösliche”︁ Stärken, zeigen eine etwa 10fache Erhöhung der Reduktivität und eine Verkleinerung der Molekulargewichte gegenüber der nativen Stärke. Den größten Veränderungen unterliegt die Röststärke ohne Chemikalienzugabe, bedeutend weniger werden der Reihe nach die mit Salz‐, Salpeter‐ und Phosphorsäure lintnerisierten Stärken verändert. Die mit α‐Amylase leicht hydrolysierten löslichen Stärken gehen, abhängig von der Reaktionszeit, in hochmolekulare bzw. mittelmolekulare Dextrine mit wachsendem Reduktionsgrad von 0,4 bis 4 DE und mit dem kleiner werdenden Molekulargewicht von 40000 bis 6000 über. Während der Hydrolyse der löslichen Stärken mit α‐Amylase in Dextrin verringert sich in den Molekülen die mittlere Anzahl der Endgruppen von 11 auf

ISSN:0038-9056    

DOI:10.1002/star.19890410803

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractEgyptian rice and maize starches were treated with sodium hypochlorite at different concentrations. The oxidized starches so obtained were monitored for carboxyl content and rheological properties. In addition, the extent and rate of the oxidation reaction was assessed by investigating the chlorine consumption. Results indicated that the extent and rate of oxidation of rice starch, expressed as chlorine consumption, are much higher than those of maize starch. The opposite holds true for the carboxyl content. Pastes of rice and maize starches before and after oxidation exhibit non‐Newtonian thixotropic behaviour but their apparent viscosity decreases by increasing the hypochlorite concentration. At any event, however, the apparent viscosity of rice starch is substantially higher than that of maize starch. Storing the pastes for 24 h adversely affect the apparent viscosity particularly with oxidized starches prepared using higher hypochlorite concentration

ISSN:0038-9056    

DOI:10.1002/star.19890410804

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractA few samples of maltodextrins procured commercially were studied in detail for some of their specific physicochemical qualities. In addition to the Dextrose Equivalent value (DE) the samples were analysed for their cold water solubility and clarity, percent age of cold water solubles, and total hydrolyzable carbohydrates. Samples were also analyzed for their hygroscopicity at different relative humidities varying from 40 to 95%. The carbohydrate profile was studied using HPLC and X‐ray diffraction pattern were taken and compared. When samples were tried for flavour encapsulation it could be noticed that samples considerably differed in their encapsulation behaviou

ISSN:0038-9056    

DOI:10.1002/star.19890410805

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe potential of the aqueous system sodium tungstate‐hydrogen peroxide for glycol‐cleavage oxidation of maltodextrins, starch andtrans‐1,2‐cyclohexanediol as a model compound has been evaluated. The peroxotungstate species formed in this medium effect oxidation of the glucose unitsviatwo major pathways: (i) glycol‐cleavage of the C2–C3 diol moieties in internal glucose units, followed by (undesired) hydrolysis of the ring‐opened intermediate and (ii) stepwise decarboxylation at the reducing terminal glucose unit until the glycosidic bond is reached. Both reaction types yield glucose oligomers terminated by erythronic acid at the former reducing end, which is an important fraction (up to 40%) of the oxidation product. Decomposition of hydrogen peroxide to oxygen and water is an inevitable

ISSN:0038-9056    

DOI:10.1002/star.19890410806

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractRecycling dialdehyde starch and similar dialdehydes were achieved by applying the benzoin condensation reaction under proper conditions that can avoid the so‐called alkaline degradation of the substrates. The products were isolated in good yield (90%) and their properties indicated the presence of the tautomoric structure (α‐hydroxyketo ⇋ enediol) forms. The desmotropy properties of the products were asserted by analytical means and by preparing the indicative derivatives. Recycling the cleaved repeating units was also supported. In general, the products belonged to polyciclicosone structure. Moreover, two types of the polymer products were obtained which differ in some of their properties, the size of the rings of their repeating units and also in their over all consti

ISSN:0038-9056    

DOI:10.1002/star.19890410807

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

Abstractα‐Amylase ofBacillus subtiliswas immobilized on acrolein‐styren copolymers of spongy and non‐spongy structures which had been modified with hexamethylenediamine followed by glutaraldehyde. Optimum bonding rates were determined from the immobilization experiments carried out with different amounts of α‐amylase, pH‐activity relationships, variation of reaction rates with the time due to the substrate diffusion limitation factor and the observed Kmvalues wer

ISSN:0038-9056    

DOI:10.1002/star.19890410808

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe results of caramelization of highly saccharified starch syrup in the presence of α‐hydroxy and α‐amino acids and their sodium salts are presented, Sodium salt of glycine as the catalyst provides the caramel of the highest tinctorial str

ISSN:0038-9056    

DOI:10.1002/star.19890410809

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19890410810

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19890410811

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY