摘要:

AbstractDSC thermograms showed that salt affected the onset temperature (T0) and enthalpy change (AH) of starch gelatinization and that the effect differed by type of salt and concentration. Anion effects seemed to parallel the structure‐making and structure‐breaking effects of water. At all concentrations, sulfate ions increased T0 and AH, but thiocyanate suppressed them. T0 and AH were affected by cations in a complex mode. In CaCl2 (3molal) or LiCl (7–10m) solution, starch gelatinized at room temperature but did not gelatinize in NaCl or KCI solutions at any concentration. Light micrographs taken at room temperature showed that in KSCN and KI solutions (>2m) starch gelatinization began at the hilum but in CaCl2 (3m) and LiCl solutions (7–10m) starch gelatinization started at the periphery. It was concluded that the mechanism of starch gelatinization in salt solutions can be attributed to: (1) structure‐making and structure‐breaking effects on water and (2) electrostatic interactions between salts and hydroxyl group

ISSN:0038-9056    

DOI:10.1002/star.19930450502

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractEs wird der Einfluß einer Behandlung mit verschiedenen pektolytischen und cellulolytischen Enzympräparaten auf die Wasserabtrennbarkeit und die Zusammensetzung von Kartoffelpulpe untersucht. Im Gegensatz zu Pektinesterase, Pektatlyase oder Cellulase zeigen Pectinex Ultra SP‐L und Pektinase/Cellulase‐Kombinationen eine starke Wirkung auf die Kartoffelpulpe. Je nach eingesetztem Enzymprä;parat sind der Gehalt an Pektin, Stärke und Protein sowie die Wasserbindungskapazität verändert. Die eintretenden Änderungen in der übermolekularen Struktur des Gewebes von Kartoffelpulpe wurden rasterelektronenmikroskopisch untersucht. Besonders durch eine kombinierte Wirkung von Pektinasen und Cellulasen wird die biologisch gewachsene Überstruktur teilweise oder weitgehend zerstört. Der Stärkegehalt der Püpepräparate bleibt auch nach intensiver Behandlung mit zellwandabbauenden Enzymen verh

ISSN:0038-9056    

DOI:10.1002/star.19930450503

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

Abstract13C‐Nuclear magnetic resonance (NMR) was used to study interaction between amylodextrin and alkali metal and alkaline‐earth metal salts in aqueous solutions. Ethyl, isopropyl and t‐butyl alcohols were used as model compounds. UC‐NMR spectra of the alcohols in potassium chloride solutions showed that carbon atoms carrying the hydroxyle groups(‐OH) were shifted up‐field, whereas those carbon atoms without the ‐OH groups were shifted down‐field. A secondary or a tertiary hydroxyl carbon was shifted to a greater extent compared with a primary hydroxyl carbon. Potassium thiocyanate was an exception. Instead of causing up‐field shifts on hydroxyl carbons in amylodextrin and in alcohols, potassium thiocyanate caused down‐field shifts of C‐1 and C‐4 of amylodextrin, a chemical shift pattern that resembled those of amylodextrin‐triiodide and other amylo

ISSN:0038-9056    

DOI:10.1002/star.19930450504

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractViscosities are given of aqueous solutions of α‐D‐glucose, sucrose, apple pectin and Arabic gum, as well as of various binary mixtures of these solutions. Aqueous mixtures of α‐D‐glucose and sucrose exhibit a small increase in viscosity. The addition of apple pectin to the binary mixtures gives solutions of a viscosity of A

ISSN:0038-9056    

DOI:10.1002/star.19930450505

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractGraft copolymerization of acrylonitrile onto Sodium salt of partially carboxymethylated starch using ceric ammonium nitrate(CAN) has been carried out in the presence of triethylamine, diethylamine, ammonia and pyridine. The percentage of grafting varied with the nature and concentration of the amines. All the amines with exception of diethylamine have been found to suppress grafting. The relative reactivity of different amines towards grafting has been determined and found to follow the order: DEA>TEA>ammonia>pyridine.

ISSN:0038-9056    

DOI:10.1002/star.19930450506

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractRecombinant genetic cloning of cyclodextrin glucanotransferase (EC 3.2.1.19) bacterial genes into E. coli has spurred the need for a rapid solid media screening analysis for recombinants. A number of qualitative and quantitative colorimetric assays have been previously developed for cyclodextrins (CDs) based on the changes in colored dye spectral response upon chelation in CDs. However, none are applicable at the screening conditions needed for recombinant E.coli (neutral pH, colored complex solid media). We report a qualitative colorimetric detection method for γ cyclodextrins produced from recombinant E. coli at neutral pH in complex media using congo red and xylene cyanole dyes

ISSN:0038-9056    

DOI:10.1002/star.19930450507

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractMolecules of hydroxypropyl‐beta‐cyclodextrin (HPBCD) in aqueous solution interact with each other via hydrogen bonds. Especially for concentrations beyond 50% (w/w), a strong increase in viscosity and a considerable decrease of freezable water can be determined. The addition of substances which are able to break the water structure (urea, KSCN) reduces these effects remarkably. The formation of inclusion compounds with urea could not be detected. Endothermic phase transformations confirm the presence of liquid crystalline structures at low temperatures. These liquid crystalline structures are not detectable at room temperatures, but the freeze fracture technique shows micelle‐like associates of a size of about 20 nm. Studies on the complexation of phenolphthalein as well as surface tension measurements of HPBCD solutions indicate that a minimum concentration of HPBC is necessary for the association phen

ISSN:0038-9056    

DOI:10.1002/star.19930450508

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractIn a step‐wise systematic selection, a strain of Endomycopsis fibuligera NRRL 76 was found to be better than the other strains tested in the production of α‐amylase and glucoamylase as well as ethanol directly from sugary and starchy substrates. Comparatively, the strain tolerated more ethanol. converted more starch to ethanol, produced less biomass and did not assimilate ethanol. There was an interrelationship between qualitative and quantitative production of amylases and ethanol production in batch fermentation with various strains. The constitutive nature of glucoamylase produced. Us lack of catabo‐lite repression and resistance to ethanol inhibition as well as the nature of starch hydrolytic products obtained, appeared to be important characteristic features in the strain for efficient conversion of starch directly to ethanol.Among a wide range of starchy substrates used in ethanol production by the yeast strains, cassava starch and waxy rice were found to be more suitable.When the strain NRRL 76 was grown optimally at pH 6.0 and 30C for 1 d under aeration followed by 3d without aeration, the maximum ethanol concentration was 92.0g/L and 73.5 g/L in media containing 300g/L and 200g/L of cassava starch respectively as compared to 73.5g/L and 77.3g/L of ethanol by another promising strain ofSchwanniomyces castelliiATCC 26077, under similar set of conditions. This process of NRRL 76 was compared with other one step processes reported in literature and found to be better than the others. The strain also converted high concentrations of cassava starch (up to 400g/L) and also waxy rice (250g/L) to ethanol satisfac

ISSN:0038-9056    

DOI:10.1002/star.19930450509

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19930450510

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19930450511

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY