Carbohydrates Flashcards
What forms the bulk of our nutrition
Carbohydrates
What type of foods are carbohydrates found in
- Almost every type
- Particularly bread, pasta and rice
- Also soluble form in soft drinks and juices
What is glucose the major fuel in and is it commonly found as such in food?
Blood plasma
- Rarely found as a major fuel source in food
What is the most commonly occurring sugar?
Disaccharide sucrose.
Where is disaccharide sucrose derived from?
Variety of plants
E.g. sugar beet and sugar cane
What is the main carbohydrate found in milk?
Lactose
What is the main carbohydrate found in mushrooms?
Trehalose
How does Glucose occur?
In two forms that are in equilibrium with each other, in ring form and linear form
(Glucose) In solution how much is found in linear form
Less than 0.1%
What are the conformations of the ring form (Glucose)
α - D - glucopyranose conformation
β- D - glucopyranose
(Glucose) In solution of the ring form what percent is found in the different conformations?
α - D - glucopyranose conformation (36%)
β- D - glucopyranose (63%)
How are (α - D - glucopyranose conformation) and (β- D - glucopyranose conformation) convertible?
Via the linear form
Which form shows that glucose is an aldehyde?
Linear form (aldehyde is fairly reactive functional group)
- This can cause problems when blood glucose levels are too high (diabetes)
What forms the majority of our nutrients
Carbohydrates
Can we digest all types of carbohydrates?
No
- Most notably Cellulose
Where is cellulose found?
Plant cell walls
Describe cellulose (structure)
Polysaccharide based on repetitive units of β (1-4) glucose
What do ruminants do?
Digest cellulose with the help of bacteria
Describe starch (structure)
Repetitions of α (1-4) glucose
Is α (1-4) glucose easily digestible
Yes
What is Agarose used for
In the food industry and bacteriology
- can not be digested by man or bacteria
What is pectin and what is it used for?
Used in food industry to solidify liquid products (e.g. custard, icecream)
- They are modified polysaccharides based on galacturonic acid
What explains polysaccharides used as solidifiers
They bind large amounts of water
