ISSN:0038-9056    

DOI:10.1002/star.19890410702

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe concentration and molecular composition of starch from alfalfa (Medicago sativaL.) taproots were determined using dimethyl sulfoxide (DMSO) extraction and gel permeation chromatography. Three 24‐h extractions with 90% (v/v) DMSO were required to solubilize an average of 97% of the starch from freeze‐dried root tissues. Amylopectin comprised approximately 80% of starch isolated from alfalfa roots. The relative proportions of amylose and amylopectin were similar among three diverse alfalfa germplasms and one cultivar even through starch concentrations ranged from 20 to 410 g kg−1dry weight. Elution profiles of debranched starches from alfalfa taproots contained two pools of low molecular weight chains with degrees of polymerization similar to debranched starches from maize (Zea mays L.), and potato (Solanum tuberosumL.). The molecular composition of starches from these alfalfa germplasms was similar to that commonly observed for most starches from cereals and t

ISSN:0038-9056    

DOI:10.1002/star.19890410703

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractProteins are found as integral components of starch granule structure. The starch granule‐bound proteins from the endosperm of nonmutant (normal) andwaxy(glutinous) cereals were extracted and subsequently separated by electrophoresis on denaturing SDS‐polyacrylamide gels. The silver stained gels revealed that for cereals thewaxyprotein (starch granule‐bound starch synthase) was approximately 60 kD. The cereals containing thewaxymutation do not show this protein. Compared to the nonmutant genotypes of other cereals, thewaxyprotein of barley,Hordeum vulgareis greatly diminished. Based on this observation, there may be reason to suspect that starch synthesis in barley varies from that of other cereals. There are minor homologous proteins among the cereals studied, including, maize, teosinte, rice, millet, sorghum, and barley. Starch granules from all cereal genotypes studied exhibited a minor protein at 68 kD. Most (81%) genotypes showed a 65 kD protein, which may correspond to a minor isozyme of starch granule‐bound starch synthase. Minor proteins occurred at 70 kD and 72 kD in 71% and 57% of the genotypes studied, respectively. The minor proteins could be isozymes of starch granule‐bound starch synthase or the proposed granule‐bound forms of branching enzyme and oligosacchari

ISSN:0038-9056    

DOI:10.1002/star.19890410704

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractPhysicochemical and functional properties of dry‐ and wet‐milled red cowpea flour, protein and starch were evaluated. Bulk density of drymilled red cowpea protein was lower than that of wet‐milled protein isolate. Dry‐milled starch was darker than wet‐milled starch. Gelatinization temperature of starch (64–68–74°C) was quite similar to that of mung bean starch. At water to red cowpea starch ratios of 3:1 and 2:1, DSC thermograms showed a single endotherm with Toof 68.5–69.0°C, Tpof 73.0–73.5°C, Tmof 79.5–80.0°C, and –ΔH of 4.0–4.6 cal/g starch. Pasting properties of red cowpea starch showed a type C amylogram, similar to mung bean starch. By mixing various quantities of red cowpea starch to tapioca starch pasting properties of the latter could be varied. Water and oil absorptions of cowpea flours increased with the increase in protein contents, as did their emulsifying activity and foaming properties. Emulsion and foam stabilities were quite similar among all the red cowpea products, except for protein isolate which were considerably lower, likely due to a greater degree of protein denaturation during precipitation and drying of the isolate. Composite flours made from mixing wheat and red cowpea flours exhibited dough mixing properties indicative of their pot

ISSN:0038-9056    

DOI:10.1002/star.19890410705

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractAlkali gelatinisation of wheat starch was found to depend on starch and alkali concentration and was faster at higher temperatures and higher alkali/starch ratios. Viscosity of an alkaline starch slurry continued to increase after bothin vitrodigestibility and soluble amylose reached maximum values. Despite extensive granule swelling, deformation and bursting, birefringence was retained to some degree indicating differences in mechanism between alkali and heat gelatinisation.

ISSN:0038-9056    

DOI:10.1002/star.19890410706

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractAus Untersuchungen geht hervor, daß die gemeinsam verwendeten Glucoamylase AMG 300 L® und Pullulanase Promozyme 200 L® in Mengen, die den in dem Präparat Dextrozyme 225/75 L Novo® enthaltenen Mengen angenähert sind, bereits nach 48 h die durch α‐Amylase verflüssigte Stärke verzuckern und, ähnlich wie Dextrozyme®, bis zu 98 DE ergeben. Die chromatographische Analyse zeigte, daß die die Glucoamylase unterstützende Pullulanase am wirksamsten ist, wenn sie gleichzeitig mit Glucoamylase gegeben wird. Daraus ergibt sich, daß Pullulanase die α‐1,6‐Bindungen leichter in niedermolekulare Dextrinen hydrolysiert als in den nach Einwirkung von Glucoamylase entstandenen Oligosacchariden G5bis G7. Beim optimalen Verhältnis der Glucoamylase und Pullulanase zur verflüssigten Stärke gibt es im Medium nach 8 h Hydrolyse nicht nur keine Isozucker (Isomaltose, Panose), sondern auch keine Oligosaccharide ab G5und Dextrine. Bei der Hydrolyse der mit α‐Amylase verflüssigten Stärke wurden mit dem Enzympräparat aus Pilzen (Fungamyl 800 L Novo®) in Mengen von 0,02–0,08%/TS, und schon nach 8 h Hydrolyse wurden 36 bis über 60% Maltose i. TS der Hydrolysate b

ISSN:0038-9056    

DOI:10.1002/star.19890410707

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractFermentation of cassava starch hydrolysate with immobilised cells ofSaccharomyces cerevisiae(Strain 2177) was carried out. Kieselguhr and brick powder were the substrates used for immobilisation of yeast cells. The pattern of fermentation was followed by the rate of fall in reducing sugar content and the cell growth. The results obtained showed that variations in the immobilised yeast cell preparations did not produce any effect on the rate of reduction of sugars during the fermentation. The final cell densities obtained after 48 h also did not depend on the initial immobilised cell concentration. However it was shown that fermentation could be completed in 48 h. It was also evident from the results that the cells were alive on the support used for immobilisation even after 4 cycles of fermentation.

ISSN:0038-9056    

DOI:10.1002/star.19890410708

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe enhancement of the tinctorial strength of caustic caramel was successfuly attempted by means of magnesium oxide applied in a catalytic amount. Also other catalysts were tested. Other changes occuring on the improving procedure were checked. Some enhancement of the tinctorial strength could be achieved by passing caramel through columns packed with anion exchangers.

ISSN:0038-9056    

DOI:10.1002/star.19890410709

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19890410710

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19890410712

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY