摘要:

AbstractStarch and gluten were isolated from flours milled from 21 Australian wheat varieties. Relative yields of starch and gluten varied in general accord with flour protein content. Recoveries of total solids (starch plus gluten) ranged from 67.6% to 85.1% amongst the varieties. Significant differences in proximate composition and amylose content were observed between the isolated starches. This was especially so for starch protein content which was significantly correlated with wheat hardness. Potential benefits exist for the starch/gluten industry in selecting wheats on the basis of minimal loss of total solids during the process, and for purity and amylose content of the isolated starch.

ISSN:0038-9056    

DOI:10.1002/star.19930450802

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractWrinkled pea starch, separated into fractions containing intact granules and fragmented granules together with small intact granules, respectively, was hydrolysed by the α‐amylase ofBacillus amyloliquefaciensin a column. The solubilisation rate was similar for both fractions and occurred in three stages: initially increasing, then slowly decreasing, and finally it was very slow. The mixtures of solubilised dextrins had DP (degree of polymerization) 2–100 and their compositions changed as the solubilisation proceeded through the different stages. The products were mostly linear and the composition of the granular residues indicated that amylose preferentially solubilised. Scanning electron microscopy could hardly reveal the site of the attack even though 20% of the granules had been solubilised. It is suggested that the enzyme attacked amylose chains in an amorphous state, whereas chain residues with DP 50–300 remained in the crystalline parts within the gr

ISSN:0038-9056    

DOI:10.1002/star.19930450803

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractA heat stable α‐amylase (Termamyl) was immobilized on controlled pore glass (CPG) with a pore size of 1 489Å and amyloglucosidase (AMG) was immobilized on a ceramic silica support (Micropil A) with a pore size of 300Å. These enzyme supports were packed into two separate immobilized enzyme reactors (IMERs) which together with a third reactor containing co‐immobilized glucose dehydrogenase/mutarotase were incorporated into a flow injection (FI) system for the determination of the total glucose content of starch related poly‐ and oligosaccharides. Samples of maltose, a maltooligosaccharide mixture, three soluble starches, three amylopectins, two amyloses, glycogen, and native starches from different origins were injected. The degree of hydrolysis was determined by comparing the produced amount of glucose in the FI system with the calculated amount of glucose in the samples and with samples to which had been added and let to react for six hours soluble α‐amylase and AMG before injected into the FI system also containing the IMERs. Virtually complete conversion to glucose was obtained for maltose, maltooligosaccharides, two soluble starches and native potato starch. Maximum enzymatic degradation by the starch hydrolyzing enzyme reactors was obtained in most instances except for glycogen (96%), native wheat (88%), rice (93%), and corn s

ISSN:0038-9056    

DOI:10.1002/star.19930450804

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractAction of porcine pancreatic andBacillus subtilisα‐amylases on native tuber starches of yam (Dioscorea alata), sweet potato (Ipomea batatas) and tannia (Xanthosoma sagittifolium) was studied in comparison with the well known potato and cassava starches. Large differences in enzymes susceptibilities were observed when studied on 24h. Yam starch was 3.5% hydrolysed with 2,8 μkat amylase/g starch, three times less than potato and tannia starches while sweet potato starch was 53% hydrolysed, two times less than cassava starch. Except yam, level of hydrolysis was higher with porcine pancreatic amylase than with theBacillus subtilisamylase while initial hydrolysis rate was lesser.Microscopic observations and image analysis pointed out that the polyhedric shaped granules of tannia, sweet potato and cassava starches were much more damaged than the spherical ones. Pitting occured preferentially on the edges of the granules and the enzymes penetrated into the starch granule by pores and canals of corrosion. Conversely to other starches, hydrolysis of yam starches evidenced greater differences between action ofBacillus subtilisand pancreatic α‐amylases. The enzymes acted by pitting some parts of the granules surface, the number of pores and their size being related to enzyme

ISSN:0038-9056    

DOI:10.1002/star.19930450805

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractRecent patents in the starch‐based plastics area have claimed melted or “destructurized” starch as a new type of material. The term “destructurized starch” has apparently been coined after the physically modified state of starch obtained by the disruption of the granular state, resulting in the loss of order and crystallinity. A brief literature review is presented which shows that, in the 1970's. starch containing low (10–30%) water contents was extruded at elevated temperatures to give a thermoplastic melt exhibiting no residual starch crystallinity. Differential scanning calorimetry studies of starch‐g‐polymethyl acrylate and blends of starch with poly (ethylene‐co‐acrylic acid) are also presented. These data indicate that these materials, prepared in the 1970's, also contain starch which was partially or completely destructurized. Thus, although ideas and uses for destructurized starch in plastic items have proliferated in recent years, completely melted or “destructurized” starch had been conceive

ISSN:0038-9056    

DOI:10.1002/star.19930450806

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractObwohl oberflächenaktive Kohlenhydratverbindungen seit langer Zeit bekannt sind, ist ihre großtechnische Herstellung erst seit wenigen Jahren aktuell geworden. Aus der Gruppe der bekannten Kohlenhydrattenside werden sich die langkettigen Alkylpolyglucoside in naher Zukunft als großvolumige Leittenside durchsetzen.Die Entwicklung der Zuckertensidchemie generell, und speziell die der Herstellverfahren für Alkylpolyglucoside, werden skizziert und die entscheidenden Produkt‐ und Verfahrensverbesserungen beschrieben, die eine unter ökonomischen und qualitativen Gesichtspunkten marktgerechte, großtechnische Alkylpolyglucosidherstellung ermöglichen.Eine Zusammenfassung der relevanten anwendungstechnischen Leistungsmerkmale der Alkylpolyglucoside vervollständigt das Bild dieser hautmilden, ökologisch und toxikologisch sehr günstig bewerteten T

ISSN:0038-9056    

DOI:10.1002/star.19930450807

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19930450808

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19930450809

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19930450810

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19930450811

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY