Types of Carbohydrates

• Simple sugars
• Smallest sugar molecules
• Polyols
• made from sugar
• Complex sugars
• polysaccharides
• Polymers of simple sugars
• fibre
• Simple Sugars
• Monosaccharides

• Hexoses
• Have six carbon atoms per molecule and have the chemical formula: C₆H₁₂O₆
• Can be absorbed without digestion
• Sweet tasting
• Can combine with other monosaccharides to make larger molecules

• Pentoses
• Five carbon sugars.which have formula C₅H₁₀O₅
• Eg Ribose, deoxyribose, arabinose, xylose
• Can be polymerised to form polysaccharides:
• Pentosans
• Used in main structure of :
• DNA & RNA
• Disaccharides
• Formed by joining two monosaccharides:
• Maltose from two Glucose
• Lactose From glucose & galactose
• Sucrose From glucose & fructose
Use of Simple Sugars
 
• As sweeteners
• good tasting
• For Consistency
• sauces, glazes, syrups
• As preservatives
• Cordials, glazed fruit, dried fruit
• jams, sweetened condensed milk
Problems with Simple Sugars
 
• The are absorbed too quickly form digestive tract.
• This Overtaxes the insulin supply
• Producing Type two diabetes

• Encourages tooth decay bacteria
• Empty kilojoules
• Not enough vitamins & minerals as needed the for catabolism of the sugars
• Sugar is not as bad as first thought. It is often the company they keep that causes the problem. Read. http://www.mayohealth.org/mayo/9606/htm/sugar.htm
Solutions to sugar problem
• Use artificial sweeteners
• Aspartame (nutrasweet), Saccharin, Sucralose
• Some are banned in USA
• Don’t have consistency
• Use of Polyols
• which have the same cosistancy as sugars
• Not absorbed therefore have no effect on energy balance or insulin
• Eat more fibre
• Slows rate of absorption
• Hidden Sugar
• Many processed foods have large amounts of sugar that may not appear obvious. Read:
• http://www.mayohealth.org/mayo/9606/htm/sugar_sb.htm
Sweetness of Sugars
• The relative sweetness of Sugars
 

Sugar	Sweetness
Lactose	0.25
Galactose	0.50
Glucose	0.56
Sucrose	1.00
Fructose	1.30

• Made from simple sugars
• Functional properties
• Vary in their sweetness and energy content, but are not absorbed

Classification of complex carbohydrates

 

Digestible Complex Carbohydrates

• All are digested slower than simple sugars and are polymers of glucose
• Starch - in plants
• Amylose ( Straight chain)
• Amylopectin ( Branched chain)
• Dextrin
• Smaller fragments of starch
• Glycogen - in meats
• branched chain
Undigestible Polysaccharides (Fibre)
• Fiber
• Non-starch polysaccharide (NSP) - Crude fibre
• Lignin
• Cellulose
• Non-cellulose polysaccharide (NCP)
• Soluble Fibre ( Dietary Fibre)
• Undigested starch
• Retrograded amylose
• b-Glucans
• Pentosans
• Inulin
• Polymers of fructose
• Pectins
• Gums
• Funtional Foods

• Foods with less fat

• Rapidly digested -
• Freshly cooked starchy foods
• Slowly digested  (+ = slower)
• Resistant starch
• ++ Raw cereals
• +++ Raw potato, carrot, etc
• Retrograde starch
• ++ Cooked then cooled starch as in :
• eg. breakfast cereals, potato salad, bread

• Digestable Carbohydrates
• Fibre

Energy

Anaplerosis

NADPH

Conversion to Pentoses

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Prepared by Barry Brazier