摘要:

AbstractStarch granules were prepared from mature kernels of sugary‐1 (su1) [sweet corn hybrid P39–5XP51—B] and its brittle‐1 (bt1), sugary‐1; brittle‐1 (su1;bt1), and normal counterparts. Amylose percentage and the distribution of linear chains of amylopectin were determined by gel filtration after debranching of the starches withPseudomonasisoamylase. Pasting characteristics by differential scanning calorimetry (DSC) and starch‐granule susceptibility to amylase were also investigated. Starch granules ofsu1;bt1maize are of a high‐amylose type, easily digestible, and have lower gelatinization temperature and smaller heat of gelatinization than those of the other three genotypes. Results obtained suggested thatbt1is epistatic tosu1for pasting characteristics of starch by DSC. However,su1is epistatic tobt1for the ratio of fraction III to fraction II of amylopectin, and amylose content and starch‐granule susceptibility to amylase are affected by b

ISSN:0038-9056    

DOI:10.1002/star.19890410502

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractIsolation and some of the important physicochemical properties of starch from rajgeera grains have been investigated. The yield of starch was about 61.2%, on whole grain basis. The results on physicochemical properties revealed that it exhibited moderate swelling and higher solubility (55.5%) in water, as compared to other millet starches. An extensive solubility in dimethylsulphoxid (72.5%) of the starch indicated easy penetration of solvent in a granular matrix, may be due to labile and heterogenous bonding forces within the granules. Brabender viscoamylographic data on pasting characteristics revealed that it yielded low viscosity (448 B. U.) at concentration of 10% (w/v) and showed very little tendency to retrograde during cooling of the starch paste. The amylopectin content was 88.5% indicating the starch of rajgeera is probably waxy in nature. Amylolytic digestibility of native and gelatinized starch of rajgeera by human salivary α‐amylase and glucoamylase was investigat

ISSN:0038-9056    

DOI:10.1002/star.19890410503

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractA‐type X‐ray diffraction spectra of raw rice was weakened upon mild parboiling and completely disappeared in moderately severe parboiled rice. A feeble V pattern of lipid‐amylose complex appeared in its place. There was no unambiguous evidence of a B‐type spectra of retrograded starch, although partial and weak B‐like spectra could be seen. Differential scanning calorimetry showed that raw rice flour and starch had a large gelatinization and a small lipid‐amylose endotherm, the latter disappearing after defatting. The gelatinization endotherm first decreased and eventually disappeared in samples with moderately severe parboiling, but a small lipid‐amylose endotherm was visible in most parboiled rice samples. On the whole, parboiled rice appeared largely amorphous with only minor crystallinity, and the peculiar properties of parboiled rice could not be definitely ascribed to a definite crystalline f

ISSN:0038-9056    

DOI:10.1002/star.19890410504

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractA method for the evaluation of freeze‐thaw stability of starch gels is described and compared with refrigerated‐storage retrogradation. Differential scanning calorimetry (DSC) is used to estimate the energy required to break down recrystallized starch molecules after 10 cycles of freezing‐thawing or after storage at 4°C for 1 week. Different DSC properties were observed for different starches. Chemical modification decreased all DSC values for gelatinization except the gelatinization range of all modified starches examined. Rice and wheat starches displayed the lowest energies of gelatinization compared with other native starches studied. Most chemical modifications completely inhibited the recrystallization of starches during storage at 4°C or after 10 cycles of freeze‐thaw. Mira‐Cleer 340® (modified regular maize starch; hydroxypropyl distarch phosphate) had a slight recrystallization value. DSC endotherms for both recrystallization studies occured at considerably lower temperatures than those of the original ge

ISSN:0038-9056    

DOI:10.1002/star.19890410505

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractRecently produced low conversion starch products (maltodextrins) contain relatively low level of mono‐ and disaccharides such as glucose and maltose. A study on obtaining starch hydrolyzates containing significant amounts of glucose and maltose without fundamental change of their dextrose equivalent was conducted. The influence of glucogenic and maltogenic amylases (NOVO) on low conversion starch products was investigated by measurement of their sugar composition, viscosity, filterability, iodine absorbance value and turbidity. The results show different properties of novel starch hydrolyzates depending on the enzymes use

ISSN:0038-9056    

DOI:10.1002/star.19890410506

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThiocarbamate herbicides were encapsulated within starch xanthate (SX) matrices to provide granules for spray mix applications. The SX granules were compared with microencapsulated (EN) and emulsifiable concentrate (EC) forms of these herbicides in greenhouse and field to determine weed contol in soil having a prior history of thiocarbamate use. The SX encapsulated thiocarbamates controlled over 80% of the weeds in 30 days. Thiocarbamate release from SX was better suited than release from EN for overcoming enhanced degradation in the field. Phytotoxicity of SX formulations was related to loss of the safener R‐25788 (N, N‐ Diallyl‐2,2‐dichloroacetamide) during form

ISSN:0038-9056    

DOI:10.1002/star.19890410507

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractNative starch, 15 min, 30 min, 45 min and 60 min hydrolyzed starches were converted to reactive carbohydratesviagraft polymerization with acrylamide followed by methylolation with formaldehyde. The reactive carbohydrates so obtained were applied to cotton fabric according to the conventional pad‐dry‐cure method under different conditions. The latter included the catalytic system and the curing conditions. The pad‐cure and the pad‐batch methods were also applicated. Examination of the treated fabrics for nitrogen content as a measure of the extent of reaction, occuring between the methylol groups of the reactive carbohydrate and the hydroxyl groups of cotton cellulose, as well as durability of the finish on the fabric indicated the dependance of the reaction and durability on nature of both reactive carbohydrate and catalyst as well as curing conditions. Reactive carbohydrate derived from 15 min hydrolyzed starch along with mixed catalyst, namely MgCl2· 6 H2O/citric acid (20:80), constitute the most appropriate finish/catalyst combination provided that application is carried out according to the pad‐dry‐cure method; drying is effected at 100°C for 2.5 min while curing is expedited at 1

ISSN:0038-9056    

DOI:10.1002/star.19890410508

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe quaternary ammonium compounds of guar gum (QAGG) and hydroxylethyl guar gum ether (QAHEG) were prepared by the reaction of guar gum (GG) or hydroxyethyl guar gum ether (HEG) with amine condensates of epichlorohydrin using either aliphatic or heterocyclic tertiary amines. These quaternary salts were characterized by infra‐red spectra, viscometry and thermogravimetry. The temperature characteristics like initial decomposition temperature (IDT), ten percent volatilization temperature (T10), temperature of maximum rate of decomposition (Tmax), integral procedural decomposition temperature (IPDT) and activation energy of QAGG and QAHEG salts are compared with those of GG and HE

ISSN:0038-9056    

DOI:10.1002/star.19890410509

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe acid hydrolysis of starch present in cassava fibrous waste results in a formation of brownish yellow hydrolysate due to the use of higher acid concentration than that needed in case of pure starch. Thus, it dictates application of stronger downstream processing unit operations such as deproteinization, clarification and decolouration. Among the various deproteinizing agents evaluated, bentonite and kaolin were found to be the best and their use resulted in the removal of 20% protein and 60–70% red as well as yellow colours. Kaolin was selected based on economic considerations. The data indicated that 5% (w/v) kaolin, 10 min contact time at 25°C and a pH of 1.0–1.5 of the hydrolysate were suitable. For complete decolouration, 0.5% (w/v) activated carbon at 25°C with a contact time of 30 min was needed. Treatment with activated carbon also results in protein removal and is maximum at 40°C. These stronger down‐stream processing unit operations lead to an acceptable product conforming to the

ISSN:0038-9056    

DOI:10.1002/star.19890410510

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19890410511

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY