Amylomaize Starch Research Articles

Evolution de quelques caractéristiques des amidons extraits de grains de maïs normal et d'amylomaïs au cours de leur formation,

AbstractThe Development of Some Characteristics of Starches extracted from Normal Corn and Amylomaize Grains during their Formation. Within the research work on the evolution of corn grains constituents with different amylose contents, during their development, a study has been carried on the starch content of corn grains, amylose content of starch grains, microscopical and submicroscopical aspects of starch grains and their crystalline organization marked by X rays diffraction.The quantity of starch synthetized for one corn grain is stated as all the more important as the amylose content of grain is lower.For amylomaizes, it is pointed out that the determination of amylose content of starch carried on at 2°C leads to higher values than at 20°C. The difference between the results might be ascribed to the presence of a glucidic fraction reacting as amylose and synthetized in a relatively important proportion at the beginning of corn grain formation, and later on becoming diluted with the other amylaceous components.The increasing stability of amylomaize starches when thermically treated might correlate with their amylose content.

Studies on starches of high amylose-content: Part X. An improved method for the fractionation of maize and amylomaize starches by complex formation from aqueous dispersion after pretreatment with methyl sulphoxide

A method has been developed of separating maize starches of different genotypes quantitatively into their component material. Pretreatment of the granular starches with methyl sulphoxide is followed by the formation of a stable, aqueous methyl sulphoxide dispersion from which the amylose component can be rapidly precipitated as an easily centrifugeable complex with butan-1-ol. The residual starch material has been subfractionated by the formation of the iodine complex at low temperatures. Properties of the different starch fractions from this fractionation scheme have been examined, and the results are briefly considered with regard to current theories of maize starches of high amylose-content.

Studies on starches of high amylose-content: Part IX. The detection of linear material in the anomalous amylopectin from amylomaize starch

Studies on starches of high amylose-content: Part IX. The detection of linear material in the anomalous amylopectin from amylomaize starch

Studies on starches of high amylose-content. : Part VIII. The effect of low temperature on the interaction of amylomaize starch with iodine: a unique characterization

The iodine-binding characteristics of amylomaize starch are affected dramatically by a lowering of temperature. At 2°, a normal-shaped, potentiometric, iodine-titration curve is obtained, from which, in contrast to results at 20°, estimation of the iodine affinity can be readily made. These conditions provide a unique method of characterization of this type of starch. Amylomaize starches having a variety of reported amylose-contents have been examined by this technique. The iodine-affinity values indicated that the starches contain some 15–18% more linear-material than expected. The iodine affinity at 2° of normal amylose and amylopectin is not appreciably different from that at 20°, but very large changes occur in the iodine-binding characteristics of samples of 36-unit amylopectin and degraded amylose at this low temperature. It is suggested that these changes account for the abnormal behaviour of the whole amylomaize starch.

Studies on starches of high amylose-content : Part IV. The fractionation of amylomaize starch; a study of the branched component

Amylomaize starches of 50% and 70% apparent amylose-content have been investigated. The iodine-binding characteristics of these starches are abnormal. The starches have been fractionated by a conventional dispersion and an extraction-sedimentation procedure. Both methods yielded a branched product having an apparent chain-length of 36 D-glucose residues, and a β-amylolysis limit of 65% conversion into maltose. Subfractionation of these anomalous amylopectins by both differential ultracentrifugation and iodine-complex formation gave fractions having properties comparable to those of normal amylopectin. It is considered, therefore, that 36-unit amylopectins in amylomaize starches are artifacts.

Studies on starches of high amylose-content : Part VII. Observations on the potentiometric iodine-titration of amylomaize starch

The abnormal character of the potentiometric iodine-titration curves obtained at 20° for amylomaize starch are not a direct result of the high amylose-content, since the comparable starch from the wrinkled-seeded pea gives a normally-shaped iodine-titration curve. It has been found that the relative extent of binding of iodine by an amylomaize depends on the method of dispersion of the starch granules. The use of dimethyl sulphoxide gave the most satisfactory iodine-binding curve. Residual contaminating protein and fat in the starch, and the inherent instability of the dispersion, do not influence the titration. Potentiometric iodine-titration curves have been obtained for a series of amylomaizes having apparent amylose-contents varying from 57 to 75%. Although the relative order of iodine sorption was in agreement with the apparent amylose-content, the curves possessed no point of inflexion, and estimations of iodine affinity were not practicable. Short chain-length amylose has been prepared, and added to normal amylopectin and to mixtures of normal amylose and normal amylopectin. It has been found that the iodine-binding characteristics of such mixtures resemble those of the anomalous 36-unit amylopectin and amylomaize starch. The significance of this finding is discussed.

Studies on Starches of High Amylose‐Content. Part VI. Observations on the Stability of Aqueous Dispersions of Waxy Maize, Maize, and Amylomaize Starches; and the Self‐fractionation of Amylomaize

Studies on Starches of High Amylose‐Content. Part VI. Observations on the Stability of Aqueous Dispersions of Waxy Maize, Maize, and Amylomaize Starches; and the Self‐fractionation of Amylomaize

Upgrading Amylose Content of Amylomaize Starch by Butanol Complexing

Upgrading Amylose Content of Amylomaize Starch by Butanol Complexing