scholarly journals The Effect of Some Extraction Solvents on the Chemical Structure of the Starches from tobacco Leaf and Potato Tubers

1962 ◽  
Vol 15 (2) ◽  
pp. 312 ◽  
Author(s):  
NK Matheson ◽  
JM Wheatley
Keyword(s):  
Absorption Spectrum ◽  
Sodium Hydroxide ◽  
Perchloric Acid ◽  
Chemical Structure ◽  
Amylose Content ◽  
Potato Tubers ◽  
Tobacco Leaf ◽  
Iodine Complex ◽  
Extraction Solvents ◽  
Mechanical Extraction

Tobacco leaf starch has been isolated as granules by mechanical extraction, and the viscosity, amylose content, f3-amylolysis limit, starch-iodine complex absorption spectrum, and apparent chain length compared with samples extracted by perchloric acid, sodium hydroxide, and chloral solution and purified as the starch-iodine complex. The efficiency of extraction of these methods was also compared. The same comparisons were made with potato granules and potato granules treated with these extracting reagents.

THE REACTION OF CARBON DISULPHIDE WITH ALUMINA

1958 ◽  
Vol 36 (2) ◽  
pp. 296-302 ◽  
Author(s):  
A. G. Pinkus ◽  
J. S. Kim
Keyword(s):  
Aqueous Solution ◽  
Absorption Spectrum ◽  
Sodium Hydroxide ◽  
Carbon Disulphide ◽  
Minimum Value ◽  
Yellow Substance ◽  
Yellow Color

The absorption spectrum in aqueous solution of the yellow substance formed by the reaction of carbon disulphide and alumina exhibits absorption maxima at 398 and 325 mμ. This yellow color is not due to sodium disulphide as previously proposed since the latter substance showed an entirely different spectrum with shoulders at about 360–375 mμ and 290–300 mμ. The presence of both water and sodium hydroxide in the alumina is necessary for the formation of the yellow color in confirmation of previous work. A study of the gain in weight of the alumina with time of contact with carbon disulphide showed that this reaction begins to level off after about 24 hours. A minimum value for the heat evolved for the alumina–carbon disulphide system was determined as 8.6 cal. per g. of alumina reacting with an excess of carbon disulphide.

Ketonization of the unusually acidic elongated enol generated by flash photolytic decarboxylation of p-formylphenylacetic acid in aqueous solution

2008 ◽  
Vol 86 (2) ◽  
pp. 101-104 ◽  
Author(s):  
Yvonne Chiang ◽  
Kirill Kolmakov ◽  
A Jerry Kresge
Keyword(s):  
Aqueous Solution ◽  
Acetic Acid ◽  
Sodium Hydroxide ◽  
Perchloric Acid ◽  
Flash Photolysis ◽  
Isotope Effects ◽  
Solvent Isotope ◽  
Solvent Isotope Effects

Rates of photolysis of p-formylphenylacetic acid were measured flash photoytically in perchloric acid and sodium hydroxide solutions, and also in acetic acid, biphosphate ion, and tris-(hydroxymethyl)methaneammonium ion buffers, using H2O and D2O as solvents. The results provide rate profiles and solvent isotope effects, which indicate that photolysis occurs through an elongated enol intermediate. This enol is unusually strongly acidic, by some two to three pQa units, when compared with simple non-elongated enols.Key words: flash photolysis, elongated enols, rate profiles, solvent isotope effects.

scholarly journals Starch Components, Starch Properties and Appearance Quality of Opaque Kernels from Rice Mutants

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4580
Author(s):  
Shun Zhang ◽  
Zheng Li ◽  
Lingshang Lin ◽  
Long Zhang ◽  
Cunxu Wei
Keyword(s):  
Absorption Spectrum ◽  
Amylose Content ◽  
Starch Synthesis ◽  
Brown Rice ◽  
Short Branch ◽  
Iodine Absorption ◽  
Appearance Quality ◽  
Starch Properties ◽  
Breeding Programmes

Rice mutants with altered starch components and properties are important genetic resources in rice breeding programmes. In this study, 44 mutants with altered starch components were screened from 135 rice mutants with opaque kernels using a starch–iodine absorption spectrum method, and nine mutants from them were further selected for investigating their starch properties and kernel appearance quality. The results showed that the iodine absorption spectrum parameters, OD620, OD620/550, and λmax, could reflect the changes of starch components in rice mutants, and had significantly positive relationships with amylose content and negative relationships with the proportion of short branch-chains of amylopectin. The endosperm starches from nine mutants all showed A-type crystalline structure and similar short-range ordered structure, but had different relative crystallinities. The changes of starch components in mutants not only resulted in the different gelatinization properties of starch but also changed the appearance quality of brown rice kernels. This study provided abundant genetic plants for studying the molecular mechanism of starch synthesis and the quality regulation of rice kernels.

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