摘要:

AbstractPreparation, physicochemical properties, pasting behavior and amylolytic susceptibility of sorghum starch have been investigated. The yield of starch was about 60.25%, on whole grain basis. The starch exhibited double stage swelling and low solubility pattern in an aqueous system. Viscoamylographic studies on pasting behaviour of the starch revealed a peak viscosity of 800 B. U. at 8% (w/v) concentration; however, it decreased considerably during cooking (viz.holding period of 30 min at 93°C). The amylose content of the starch was 23.45%. The gelatinization temperature range was found to be 68.5–72.5–78.5°C. The results indicated that the native starch hydrolyzed to a limited extent by human salivary α‐amylase and glucoamylase as compared to gelatinized starch. In addition, the mode of attack by amylolytic enzymes on the native starch granules viewed by SEM has been studied i

ISSN:0038-9056    

DOI:10.1002/star.19890410402

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThein vivodigestibility of the following chemically modified potato starch derivatives was evaluated in rats; distarch phosphate (DSP), acetyl di‐starch phosphate (ADSP) and hydroxypropyl di‐starch phosphate (HPDSP). Unmodified potato starch was used as reference. The starches were studied raw and after gelatinization by drum‐drying. The extent ofin vivodigestion was evaluated through balance experiments in normal rats (apparent digestibility) and in rats treated with an antibiotic drug to suppress hind‐gut fermentation (true digestibility). Starch digestibility was calculated from direct measurement of starch in feed and faeces. Three different methods for starch analysis were compared.The apparent digestibility of raw potato starches was low, ranging from 50 (HPDSP) to 84% (ADSP). The true digestibility of gelatinized unmodified potato starch was essentially complete and was not affected to any appreciable extent as a result of cross‐linking or acetylation. In contrast, etherification with hydroxypropyl significantly reduced the extent of digestion and absorption to a low level, about 50%, which was not significantly different from that with the corresponding raw material. Thus, the digestibility of the HPDSP derivative was not improved by gelatinization. The maldigested hydroxypropylated starch fraction was only metabolized to a limited degree by the hind‐gut mic

ISSN:0038-9056    

DOI:10.1002/star.19890410403

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractRefined legume starches were evaluated for their Brabender Visco/Amylograph properties in their native form and after chemical and enzymatic pretreatment during incubation for 20 h at room temperature. Although exhibiting the characteristic restricted paste viscosities of legume starches, native lentil starch showed much higher viscosity parameters than navy bean starch while field pea starch had very low, stable viscosities. Pretreatments with mineral acids, alkali or enzymes failed to significantly alter the amylographs of the 8% slurries (w/v). Removal of surface lipids on the refined starch granules with propanol/water (3:1 v/v) or chloroform/methanol (2:1 v/v) increased paste viscosities substantially, as did the complexation of the starches with palmitic acid or glyceryl monopalmitate. None of the treatments resulted in complete dissolution of the starch granules and the modified starches showed no improvement in gel syneresis during storage.

ISSN:0038-9056    

DOI:10.1002/star.19890410404

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractHydrogels with moderate water retention capacity and salt stability have been prepared from starch, oxidized starch, and amylopectin all crosslinked with epichlorohydrin. The swelling power was measured in water and in various salt solutions of different concentrations. The swelling capacity decreases with increasing both the crosslinker and the polymer concentration. The plateau modulus (G′p) of the prepared gels was determined from complex dynamic viscosity measurements. G′pwas measured as a function of the epichlorohydrin and polymer concentrations. The loss modulus (G″) for the prepared gels was also measured and was always found to be almost zero. The molecular weight between two entanglement points (mesh width) was estimated from the G′pvalues. The ratio between the number of elastically effective entanglement points, calculated from the G′pvalues, and that calculated from complete conversion of the cross‐linker was also estimated for various gels. It was found that this ratio is very small (0.2–0.7%) for gels prepared with 10 wt‐% starch, it increases however to 13% at higher starch concentra

ISSN:0038-9056    

DOI:10.1002/star.19890410405

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe nature of a particular type ofin vitroundigestible starch, i.e. resistant starch (RS), was studied. This type of undigestible starch is found in products processed at relatively high moisture contents, such as baking and autoclaving. The RS was concentrated by enzymic digestion of available starch and protein and recovered by centrifugation.RS from autoclaved wheat starch was evaluated by various methods. The crystallinity was studied by X‐ray diffraction and DSC. The degree of polymerization (DP) was evaluated with gel permeation chromatography and iodine binding and the starch content and linearity by enzymic methods. The results indicate that RS consist of crystallized, linear α‐glucans of relatively low molecular weight (DP approx. 65).The recovery of RS after various drying procedures, and the introduction of a thermostable amylase (Termamyl®) in the RS assay was also studied. Oven‐drying of the fibre residues used in the analysis had no significant effect on RS recovery, whereas freeze‐drying was accompanied by a slight increase in RS content. The use of Termamyl®, in the assay of RS in the fibre residues, decreased the yield of RS

ISSN:0038-9056    

DOI:10.1002/star.19890410406

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractFormation of cyclodextrin (CD) from soluble starch byBacillus maceransCGTase (cyclodextrin glucanotransferase) was studied experimentally in both systems with and without the addition of ethanol. The yields of α‐, β‐ and γ‐CD after long time reaction were almost independent of initial concentration of starch (5–50 g/l) in both the systems. The α‐CD yield in the presence of ethanol was increased by 1.8–1.9 times of that in the absence of ethanol, while the β‐CD yield was decreased by the amount almost comparable to the increase in α‐CD yield. Initial rates of CD formation were decreased with increasing ethanol concentration, which was remarkabl

ISSN:0038-9056    

DOI:10.1002/star.19890410407

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractA modern glucose isomerization system has been developed which differs from conventional immobilized systems which use isomerases such as crosslinked cell‐based products; the latter are discarded after enzyme inactivation. The newer system consists of two separate phases: an inert, regenerable carrier that has a high protein binding capacity, and an enzyme solution containing a pure isomerase protein. This system offers different possibilities for the immobilization: Batch immobilization loading the carrier fully with the enzyme.Batch immobilization loading the carrier only partly with the enzyme.Continuous or semi‐continuous loading of the carrier with enzyme during the isomerization process.The technique of a gradual addition of enzyme to the column during the isomerization process, which is called „on‐column loading”︁, is a flexible system providing several advantages compared to the traditional isomerization technology Initial flow rate according to current needs. Flexible capacity adjustable according to the syrup need of the markets. Few isomerization columns needed for stable and even operation. simple to operate. Uninterrupted operation for up to two years. Low isomerization costs.This technology has been successfully tested in plant scale in several HFS plants, and one plant has been totally designed to be operated with this technology. this plant has been in operation for more than 1.5 years with the full satisfaction

ISSN:0038-9056    

DOI:10.1002/star.19890410408

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19890410409

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19890410410

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19890410411

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY