ISSN:0038-9056    

DOI:10.1002/star.19950470102

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractGelatinization and solubility characteristics of starch contribute to unique functionality in foods. Corn and oat starch viscoamylographs (35g db) showed peak viscosities of 400 and 390B.U., respectively. Oat starch had a more rapid (89.7 vs 85.6°C) and higher set back (790 vs. 740B.U.) than corn. Data on soluble components of cooled (85°C) starch pastes, as collected and analyzed by high‐performance size exclusion chromatography (HPSEC), suggest that amylopectin plays a significant (P<0.05) role in oat paste set back; for corn starch, amylose is the dominant factor. Solubilities and apparent molecular weights (MW) of oat starch heated (65‐120°C) under shear and subsequent sonication (0‐40s) in water or 90% methyl sulfoxide (DMSO) were also determined by HPSEC. An intermediate MW fraction was eluted on the HPSEC chromatograms only when oat starch was heated in water (100‐120°C/30min) or DMSO and sonicated, suggesting that this fraction may not be inherent in the native granule. in water, polymer solubility and peak MW increased with temperature (65‐120°C), whereas in DMSO, solubility decreased with heating (65‐100°C), while peak MW remained basically constant. Aqueous (aq) leaching at 75°C solubilized more corn amylose than amylopectin, but amylopectin and amylose co‐leached from oat starch granules. Aq leaching, at 20°C above their DSC peak ends (85 and 95°C for oat and corn, resepctively), showed more amylopectin leached from oat starch granules whereas more amylose was leached fro

ISSN:0038-9056    

DOI:10.1002/star.19950470103

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractA study of eight commercial parboiled samples derived from two varieties of rice produced by four different processes has shown that depending on the parboiling process, the starch component itself can be present as native and/or retrograded starch in addition to the amylose‐lipid complex. Further, it was demonstrated that the polymorphic states of starch can influence the texture and behaviour of cooked rice. The parboiled rice samples which had all three states of starch (i.e. ungelatinized and recrystallized amylopectin plus the amylose‐lipid complex) possessed the hardest eating property but the lowest solubility. A negative linear relationship was demonstrated between the hardness and the solubility of cooked, parboiled rice. Overall, the observations suggest the existence of different forms of starch in parboiled rice which vary with the different parboiling protocols. The conditions governing their formation need to be established before investigating the specific functionality of individual forms within the rice. This study further confirmed that retrograded starch (amylopectin) in parboiled rice did not exhibit a B‐tye X‐ray pattern but mixed A+V p

ISSN:0038-9056    

DOI:10.1002/star.19950470104

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractThe physicochemical properties and functional characteristics of starch from a high β‐glucan waxy barley were compared with those of starches isolated from normal and high amylose barleys. Amylose content of the starches ranged from 1.9 to 34.8%. There was no relationship between amylose content and water binding capacity and gelatinization temperature of the starches. Amylose content and swelling power as well as enzyme susceptibility were negatively correlated. Waxy barley starches had a lower solubility than amylose‐containing starches. High amylose barley starch registered no swelling in the Amylograph. Amylose content in starch proved to be very important for good bread‐ and cake baking quality. Waxy starches did not produce acceptable breads and cakes.The starch from the high β‐glucan barley variety “Shonkin” will be suitable as a thickening agent, but not as an ingredient in ba

ISSN:0038-9056    

DOI:10.1002/star.19950470105

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractPotato starch was oxidized by hydrogen peroxide in alkaline and acidic reaction conditions with copper, iron and tungstate catalysts in order to introduce carboxyl and carbonyl groups to the starch molecule. Carbonyl contents up to 6.6 per 100 glucose units could be obtained, whereas carboxyl content remained low (up to 1.4). Starch yields in the alkaline and acidic reactions were 90 and 99%, respectively. The molecular weight decreased markedly with the degree of oxidation, and was dependent on the catalyst used. Rheological measurements revealed that when the molecular weight of the moderately oxidized starch was high, a very firm gel (G' = 40kPa) was obtained with 25% starch concentration. When the degree of oxidation increased, the storage modulus G' decreased. The more the oxidized starch contained carbonyl groups, the higher was the gelatinization temperature.

ISSN:0038-9056    

DOI:10.1002/star.19950470106

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractD(—)‐Fructose, dextrose and sucrose were thermally decomposed in the presence of native and pregelatinized corn starch, cellulose as well as its mixtures with native corn starch. Several products were obtained in which reactive intermediates thermally generated from lowmolecular saccharides were involved. When starch either was not gelatinized or it could not gelatinize on reaction, the preference for the formation of a physical mixture of caramel with starch and starchsugar complexes was observed. Otherwise products of substitution of starch with reactive intermediates and inclusion complexes were formed. Cellulose appeared to be more reactive. It was grafted to starch by reactive intermediates thermally generated from dextr

ISSN:0038-9056    

DOI:10.1002/star.19950470107

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractPolyelectrolyte complexes (PECs) have been prepared by mixing solutions of carboxymethyl starch and diethylethylamino starch at ionic substituent mixing ratios of 0.2, 0.5, and 0.8. The complexes were insoluble in water, although they did swell to some extent. Interactions between ionic groups were examined using turbidity measurements and FTIR spectroscopy. Supernatant turbidity was the lowest when the mixing ratio was equal to 0.5. The degree of carboxylate neutralization as measured by FTIR increased with mixing ratio. Complex formation was completely suppressed when NaCl was present in concentrations greater than approximately 0.10m. These results indicate that complex formation was due to ionic crosslinks between the oppositely charged starch molecules.

ISSN:0038-9056    

DOI:10.1002/star.19950470108

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractThe effects of extrusion conditions (feed moisture content and rate, process temperature, screw speed and geometry, and die diameter) on expansion ratio, bulk density, and breaking strength of wheat flour extrudates were investigated. Extrudate samples were prepared by using a Brabender single‐screw extruder. Higher feed moisture content and process temperature were required for proper expansion. At 3.18mm die opening, the relationship between expansion and bulk density was positive. Feed rate was the most effective factor for increasing bulk density. Breaking strength was significantly decreased with increasing process temperature.Under extrusion conditions of 22% feed moisture, 110g/min feed rate, 160°C process temperature, and 130rpm screw speed with 5:1 CR, wheat flour was puffed with low bulk density and breaking streng

ISSN:0038-9056    

DOI:10.1002/star.19950470109

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

摘要:

AbstractAqueous potato pulp suspension of 5% d.s. was subjected to streaming under pressure of 1 atmosphere for 1h and, subsequently, bounded starch was enzymatically liquefied and saccharified, insoluble suspension was filtered and rest of sugars was washed out with hot water and dried to obtain a fiber preparation containing 79% d.s. of dietary fiber. The fiber preparation produced from raw pulp contained only 71.7% d.s. of dietary fiber. For baking of bread wheat meal containing 0,5% and 10% of the fiber preparation obtained from potato pulp was used. Organoleptic tests and physico‐chemical properties of wheat bread containing 5% fiber preparation in relation to wheat meal, appeared to be as good as in bread without this preparation. However, bread containing the fiber preparation was healthier for consumer

ISSN:0038-9056    

DOI:10.1002/star.19950470110

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19950470112

出版商:WILEY‐VCH Verlag GmbH    

年代:1995

数据来源: WILEY