Starch hydrolysis products. Determination of reducing power and dextrose equivalent. Lane and Eynon constant titre method

2015 ◽  
Keyword(s):  
Reducing Power ◽  
Starch Hydrolysis ◽  
Dextrose Equivalent ◽  
Hydrolysis Products

COMPARISON OF VARIOUS METHODS FOR THE CHEMICAL ASSAY OF CORTICOIDS IN URINE

1955 ◽  
Vol 18 (4) ◽  
pp. 374-378
Author(s):  
Mogens Sprechler
Keyword(s):  
Calibration Curve ◽  
Periodic Acid ◽  
Reducing Power ◽  
Standard Technique ◽  
Phosphomolybdic Acid ◽  
Florisil Column ◽  
Chemical Assay ◽  
Chromatographic Procedure ◽  
Acid Reagent

SUMMARY Since 1949 about 10,000 urinary corticoid analyses have been performed routinely in our laboratory. The method used for this purpose was described in 1950 (Sprechler). We determine the corticoids which can be extracted from the urine with chloroform immediately after acidification to pH 1. The extract is washed with sodium hydroxide and water, a Girard separation is performed, and finally the reducing power of the ketonic fraction is measured by means of the phosphomolybdic acid reagent reaction. During the last few years two other chemical reactions have been used for comparison: The formaldehyde and the Porter-Silber method. After a thorough examination of the above methods a standard technique was followed. In the formaldehyde method a microdiffusion in a Conway unit was used instead of distillation of the formaldehyde following the oxidation with periodic acid. The calibration curve was corrected for loss of material by taking the standard doses of DOC through all the procedures of the method. A micromodification of the Porter-Silber method was chosen. Furthermore attempts were made to determine how specific the chromatographic procedure is in the determination of steroids in urinary extracts. For this purpose the Florisil column was used, and the technique described by Nelson & Samuels was followed. Finally we have investigated the glucuronide-bound corticoids in urine in a smaller series of objects.

scholarly journals Influence of the Liquefied Starch Composition and pH on the Saccharification at the Obtaining of Maltose Syrup

1970 ◽  
Vol 66 (2) ◽  
Author(s):  
Monica MIRONESCU ◽  
Ion Dan MIRONESCU ◽  
Adrian TRIFAN ◽  
Maya IGNATOVA ◽  
Vionela MIRONESCU
Keyword(s):  
Enzymatic Activity ◽  
Strong Influence ◽  
Degree Of Polymerisation ◽  
Dextrose Equivalent ◽  
Hydrolysis Products ◽  
Starch Composition ◽  
Maltose Syrup

In this paper the influence of the composition of the liquefied starch and of pH on the quality of saccharification at the obtaining of maltose syrup is investigated. A large number of experiments (68) in various liquefaction conditions show that Dextrose Equivalent (DE) and the composition in hydrolysis products with Degree of Polymerisation higher as four (DP ≥4) in the liquefied starch have a strong influence on the saccharification products, mainly on the maltose content in the maltose syrups. The liquefied starch with DE lower as 25 has smaller amounts of DP ≥4 (40 to 60%), whereas the liquefied starch with DE between 25 and 27 has high amounts of DP ≥4 (60 to 80%). For the production of maltose syrups, the liquefied starch must have DP ≥4 in high percentage (≥70%); the optimal yield in maltose at saccharification is attired when the proportion of DP ≥4 is 70%. pH influences strongly the enzymatic activity of the enzyme Optimalt BBA used at saccharification; the pH interval for the obtaining of maltose syrups is 4.7 to 5.4. The saccharification at lower or higher pH doesn’t allow the obtaining of maltose syrups.

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