摘要:

AbstractThe determination of the quantity of starch per volume (kg/m3) in a slurry of potato starch in water by measuring the density of the slurry with a standard areometer and the temperature is reviewed. A formula is developed in which occur two physical constants of potato starch (soaked in water): the density at 20°C and the temperature correction factor. The constants are calculated from measurements in starch slurries. In this report the method is given. A limited number of recent measurements resulted in the given preliminary constants. It showed that the density of the starch (soaked in water) differs between never dried starch and dried and reslurried starch. Starch tables can be made with the help of the developed formulas

ISSN:0038-9056    

DOI:10.1002/star.19920440802

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe alkali steeping process was tested for extraction of starch from degerminated yellow corn flour. The effect of three process parameters, alkali concentration (0.1 and 0.4%), steep temperature (25 and 55°C) and steep time (30 and 90min) were evaluated for their effect on yield, protein and sodium contents of starch. Two‐level full factorial design was used to investigate the process. The experimental results indicated that starch yield increased with increasing steep temperature and at low alkali concentration. All main effects and interactions were found to have significant effect on protein content in the extracted starch. The sodium content of the starch was effected by the three main effects and the three two‐factor interaction effects. Conditions were identified that simultaneously produced a high starch yield, low protein and sodium contents were 0.1% alkali steep at 55°C for 3

ISSN:0038-9056    

DOI:10.1002/star.19920440803

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA rapid and non‐destructive pulsed NMR method of monitoring starch retrogradation was developed based on the principle that the signals from protons in the “solid‐like” and liquid components in a system decay at significantly different rates following a 90° radio‐frequency pulse. As molecular association or recrystallization proceeds during aging of a starch gel, the proportion of the “solid‐like” component in the system increases. The resulting decrease in segmental mobility of the starch chains causes a decrease in the signal from the liquid component, but a concomitant increase in the signal attributed to protons in the “solid‐like” fraction. The method was applied to study the retrogradation tendency of starches from diffe

ISSN:0038-9056    

DOI:10.1002/star.19920440804

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractResearch on starch‐based biodegradable plastics began in the 1970's and continues today at the National Center for Agricultural Utilization Research (NCAUR) in Peoria, IL. Technology has been developed for producing extrusion blown films and injection molded articles containing 50% and more of starch. Extrusion processing of compositions containing starch and other natural polymers to provide totally biodegradable plastics is being investigated. Starch grafted with thermoplastic side chains is under commercial development to provide injection molded items with a broad range of compositions and properties. The mechanism of biological degradation and the rate and extent of biodegradation of starch containing plastics in various environments is studied to enhance development and acceptance of biodegradable plastic

ISSN:0038-9056    

DOI:10.1002/star.19920440805

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractStarch‐N‐methylol acrylamide methacrylic acid cation exchange composites were synthesized by polymerizing of highly concentrated aqueous mixtures of methacrylic acid and N‐methylol acrylamide with starch using ammonium peroxydisulphate, as an initiator, alone and with different reductants, viz. sodium thiosulphate, sodium pyrosulphite and glucose. Sodium thiosulphate proved to be the best reductant that can produce the composite at the lowest solidification time with the highest insoluble yield and carboxyl content. Factors affecting the process such as temperature, redox system concentration and concentrations of monomers were reported. Four kinds of cation exchange composites, of different nitrogen and carboxyl contents, were prepared. These composites were characterized by potentio‐metric titrations, water solubility and swellability, as well as durability

ISSN:0038-9056    

DOI:10.1002/star.19920440806

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractAlthough water soluble synthetic polymers find wide applications as flocculating agents, the potential problem associated with their use is lack of biodegradability and high cost. Development of substitutes based on natural polymers can be more attractive from biodegradability point of view and the important factor here will be matching the performance.We have studied the flocculating effects of starch derivatives (cationic and anionic) for ferric soap flocculation at different pHs and compared their efficiency with synthetic flocculants like Zeetag‐63 and Floc‐acid‐25. Charge interaction between colloidal particles and polymeric flocculating agents is one of the factors that contribute to the changes in rae and extent of flocculation. :Under certain pH conditions starch based flocculants are shown to perform better than the synthetic flocculants (Zeetag‐63) and the effects are explained on the basis of variation of surface charge (measured by collid titration) of ferric soaps precipitated at differ

ISSN:0038-9056    

DOI:10.1002/star.19920440807

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractDuring growth ofC. thermosulfurogenesEM1 on starch, seven forms of pullulanase and one form of α‐amylase were detected after gel electrophoretic separation of proteins. By determining the isoelectric points and N‐terminal sequences of various pullulanase species it was evident that no structural differences exist between these proteins. These pullulanases hydrolyzed α‐1,4‐ and α‐1,6‐linkages in various soluble sugar polymers causing their breakdown to maltose and maltotriose. Unlike these enzymes, the α‐amylase produced byC. thermosulfurogenesEM1 preferentially attacked non‐soluble starch. The main product of hydrolysis was maltohexaose. The combined action of pullulanases and α‐amylase on native starch showed synergistic effect. This synergistic effect was not observed if soluble starch

ISSN:0038-9056    

DOI:10.1002/star.19920440808

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractCyclodextrinase is an enzyme that hydrolyzes cyclodextrins. Some amylolytic enzymes can also hydrolyze cyclodextrins. A comprehensive review of these cyclodextrin degrading enzymes and their action pattern is presented.

ISSN:0038-9056    

DOI:10.1002/star.19920440809

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe immobilization of glucoamylase by entrapping in a polyacrylamide gel has been studied. The optimum values of pH and temperature for the immobilized enzyme have been determinated. The influence of worked off cycles, substrate concentration and initial degree of hydrolysis on the final conversion of starch have been investigated.

ISSN:0038-9056    

DOI:10.1002/star.19920440810

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19920440811

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY