Diploma in Hospitality Management
Nutrition Lecture Four
Carbohydrates
Types of Carbohydrates
- Simple sugars
- Smallest sugar molecules
- Polyols
- made from sugar
Complex sugars
polysaccharides
Polymers of simple sugars
fibre
Simple Sugars
Monosaccharides
These are the smallest sugars
Can have 3 to 7 carbons per molecule
- 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
Eg Disaccharides
and Polysaccharides
- Pentoses
- Five carbon sugars.which have formula C5H10O5
- Eg Ribose, deoxyribose, arabinose, xylose
- Can be polymerised to form polysaccharides:
- Used in main structure of :
monosaccharides:
- eg Maltose from two Glucose
- Lactose
From glucose & galactose
- Sucrose
From glucose & fructose
Use of Simple Sugars
As wweeteners
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
Solutions to sugar problem
Use artificial sweeteners
Aspartame (nutrasweet), Saccharin, Sucralose
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
Sweetness Of Sugars
The relative sweetness of Sugars
Sugar: Lactose Galactose Glucose Sucrose Fructose
RSP: 0.25 0.50 0.56 1.00 1.30
Polyols (or "sugar alcohols")
- Made from simple sugars
- Functional properties
- Vary in their sweetness and energy content, but are not absorbed
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
Non-cellulose polysaccharide (NCP)
Soluble Fibre ( Dietary Fibre)
Undigested starch
b-Glucans
Pentosans
Inulin
Pectins and Gums
Are food that have proven to give a non -nutritional health benefits that
Many of these are dietary fibers
Use fibre as a fat replacement
Bowel digestibility of starch types
Rapidly digested -
Freshly cooked starchy foods
Slowly digested
Resistant starch
- ++ Raw cereals
- +++ Raw potato, carrot, etc
Retrograde starch
++ Cooked then cooled starch as in :
- eg. breakfast cereals, potato salad, bread
The End
Or