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Chapter-02 Reactions of carbohydrates

BOOK TITLE: Laboratory Manual for Practical Biochemistry

Author
1. MK Ganesh
2. A Hemavathi
3. YM Shivaraja Shankara
ISBN
9788184482591
DOI
10.5005/jp/books/10435_3
Edition
1/e
Publishing Year
2008
Pages
8
Author Affiliations
1. KVG Dental College, Sullia, Karnataka, KVG Dental College, Sullia, Karnataka, India
2. KVG Medical College, Sullia, Karnataka
3. KVG Medical College, Sullia, Karnataka, KVG Medical College, Sullia, Karnataka, India
Chapter keywords

Abstract

Molisch test is the general reaction of carbohydrates. Iodine test is answered only by polysaccharides. Benedict’s test is answered by reducing sugars; as a semiquantitative test it approximately gives the percentage of sugars in urine. Osazones are the crystalline substances formed from reducing sugars, and glucose and fructose form identical osazones of needle shape. Osazones of lactose and maltose have hedge hog and sunflower shapes respectively. Seliwanoff’s test distinguishes between aldo and keto sugars, and fructose being a keto sugar gives a positive Seliwanoff’s test. Barfoed’s test helps to distinguish between monosaccharides and reducing disaccharides.

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