LOGO Course lecturer : Jasmin Šutković 23th May 2016 Chemistry - SPRING 2016 Lecture 12:Carbohydrates

Content  Introduction  What are carnohydrates?  Types of Carbohydrates?  Chiral molecules  Monosacharides-properties  Disacharides-properties  Polysacharides  Real life examples

Introduction  Carbohydrates are the most abundant of all the organic compounds in nature.  In plants, energy from the Sun converts carbon dioxide and water into the carbohydrate glucose.  About 65% of the foods in our diet consist of carbohydrates

Carbohydrates  Carbohydrates such as table sugar, lactose, and cellulose are all made of carbon, hydrogen and oxygen.  Simple sugars, which have formulas of Cn(H2O)n, were once thought to be hydrates of carbon, thus the name carbohydrate!

Types of Carbohydrates

Monosacharides

Chiral molecules

 Your hands are mirror images that cannot be superimposed on each other.  When the mirror images of organic molecules cannot be completely matched, they are nonsuperimposable.

Examples...

Monosacharides C6H12O6 The most common hexose, Glucose, C6H12O6, also known as dextrose and blood sugar, is found in fruits, vegetables, corn syrup, and honey, d-glucose is a building block of the disaccharides sucrose, lactose, and maltose, and polysaccharides such as amylose, cellulose, and glycogen. Galactose, C6H12O6, is an aldohexose that is obtained from the disaccharide lactose, which is found in milk and milk products. Galactose is important in the cellular membranes of the brain and nervous system Fructose C6H12O6, is a ketohexose. The structure of fructose differs from glucose at carbons 1 and 2 by the location of the carbonyl group. Fructose is the sweetest of the carbohydrates, almost twice as sweet as sucrose.

Disacharides

Lactose  Lactose, milk sugar, is a disaccharide found in milk and milk products  Lactose makes up 6 to 8% of human milk and about 4 to 5% of cow’s milk, and it is used in products that attempt to duplicate mother’s milk. When a person does not produce sufficient quantities of the enzyme lactase, which is needed to hydrolyze lactose, it remains undigested when it enters the colon. Then bacteria in the colon digest the lactose in a fermentation process that creates large amounts of gas including carbon dioxide and methane,nwhich cause bloating and abdominal cramps.  In some commercial milk products, lactase has already been added to break down lactose.

Sucrose  Sucrose, a disaccharide obtained from sugar beets and sugar cane, contains glucose and fructose