摘要:

AbstractIt is concluded that granule swelling is required for any chemical derivatization of common yellow dent maize starch with fatty acyl chlorides in organic solvents, even for reaction at granule surfaces. It was also concluded that progressively less of hot pyridine‐swollen granules is available for reaction with fatty acyl chlorides as the carbon chain length increases from C6to C14, with those two lengths being the approximate outside limits for partial exclusio

ISSN:0038-9056    

DOI:10.1002/star.19920440902

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractComparative studies on the physico‐chemical and functional properties of the cassava starches, obtained by conventional and enzyme‐integrated conventional techniques, indicated no adverse chemical modifications and nearly equal X‐ray diffraction patterns as well as granular structure. The starch obtained by enzyme‐integrated technique has 50% lower ash content and nearly double water solubility at room temperature. The swelling power, the swelling volume and the viscosity indices were slightly lower. Better cooking properties of the starch isolated by enzyme‐integrated technique is indicated by its lower set‐back viscosity. The data thus indicate a number of improved properties of cassava starch manufactured by enzyme‐integrated conventio

ISSN:0038-9056    

DOI:10.1002/star.19920440903

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractUnisolated rice starch was obtained by wet milling of broken milled rice grains. Hydroxypropyl rice starches of different level of molar substitution (MS) were prepared and characterized. Both native and modified starches were treated with calcium carbonate at various calcium: starch ratios. Binding was markedly influenced by the calcium concentration in the reaction mixtures. Native starch binds less calcium than modified starch. Ability to bind calcium decreased with increasing calcium concentration in both native and modified starches. A parallel increased in calcium binding was observed as MS increased to the value of 0.09 and thereafter reversed. Increased level of substitution depressed the optical rotation and electrical conductivity of starch‐calcium comple

ISSN:0038-9056    

DOI:10.1002/star.19920440904

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractUrea, various glycols and mixtures of these were tested as plasticizers for gelatinized cornstarch. Mixtures of cornstarch, urea and/or triethylene glycol, glycerol or propylene glycol were extruded into ribbons. Mechanical and structural properties of the ribbons were evaluated by tensile testing, DSC and NMR. Flexible ribbons were obtained only when enough urea or glycol was present to lower the glass transition temperature of the starch near or below room temperature. Ribbons containing high levels of urea were rather stiff, reflecting the low mobility of urea. Ribbons containing high levels of glycol were, in contrast, soft and weak. Samples extruded with mixtures of urea and glycols exhibited enhanced elongations at break. All samples became brittle at very low humidities and soft at high humidities.

ISSN:0038-9056    

DOI:10.1002/star.19920440905

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA simple procedure is devised to extract β‐amylase preparation in a form suitable for commercial applications from germinated barley. α‐Amylase activity in the β‐amylase preparation was negligible to warrant its further purification. This preparation showed enzymatic activity over a broad pH and temperature range, suitable for conversion of starch to high purity

ISSN:0038-9056    

DOI:10.1002/star.19920440906

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractEffects of enzyme concentration, substrate concentration and residence time on substrate conversion, reactor capacity and productivity were evaluated. As enzyme concentration increased from 1 to 6 g/L, substrate conversion also increased. Substrate conversion was essentially unchanged at enzyme concentrations greater than 6 g/L. Reactor capacity was significantly affected by both substrate and enzyme concentration. As residence time increased, substrate conversion increased 15–22%. Productivities of the continuous reactor were 10 to 20 times greater than those obtained in a batch reactor. The continuous membrane reactor was capable of producing a highly pure glucose syrup at low residence times. Due to the high levels of substrate conversion, minimal operational problems were experience

ISSN:0038-9056    

DOI:10.1002/star.19920440907

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractFouling of the hollow‐fiber ultrafiltration membrane was not significant. However, there was a considerable difference in the steady‐state permeate flux for each of the solutions studied. The feed solution containing 300 g/L glucose and 33 g/L liquefied starch resulted in the lowest steady‐state flux of 1.48L/m2/h (LMH). Performance of the membrane as a function of transmembrane pressure, and flow rate was also evaluated. At a given transmembrane pressure, flow rate had no effect on permeate flux indicating that the membrane module was operating in the pressure controlled region. Concentration polarization effects were also minimal at the operating conditions studied. At the enzyme concentrations employed in these studies, loss of enzyme activity due to membrane leakage, mechanical shear, thermal inactivation and/or membrane “poisoning” had little effect on reactor stability and glucose p

ISSN:0038-9056    

DOI:10.1002/star.19920440908

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19920440909

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19920440910

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19920440911

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY