Carbohydrates Flashcards
1
Q
Monosacchrides
Carbohydrates
A
Simple sugars
* Glucose/dextrose
all converted to glucose in the body (digestion)
sugars found in bloodstream
ie. ripe fruit + veg
* Fructose
Fruit sugars
ie. fruit, plant juices
* Galactose
milk of mammals
forms part of milk sugars (lactose)
* invertose/invert sugar
honey
- Glucose glycogen in the body
- Can be converted to fat used for energy
- Simple carbs found in processed +
refined sugars
ie. sweets, table sugars, syrups,
carbonated beverages - Refined sugars
provide calories - lack vitamins, minerals,
fibre
often called ‘empty kilojules’
lead to weight gain / obesity
ie. cakes, pastries, condiments
2
Q
Disacchrides
Carbohydrates
A
- combinations of 2 monosacchrides
- ‘double sugars’
- glucose + fructose = sucrose
> cane/beet sugar (table sugar) - glucose + galactose = lactose
> milk sugar - glucose + glucose = maltose
> malt sugar (starch hydrolyses)
3
Q
Polysacchrides
Carbohydrates
A
- many simple sugars
- starch, glycogen, pectin, dietary fibre (cellulose)
- starch
> major form stored carbs in plants
> found in fruits and veg - glycogen
> stored in glucose in animals and humans
> stored in liver and muscles - sent to bloodstream (instant energy) - pectin
> gelling substance
> found in ripe fruit - fibre
> soluble or insoluble
> cellulose (bran) in whole-wheat flour, bran, whole grains
> hemicelluloses in bran and whole grains
> lignin in mature veg, wheat, fruits with edible seeds
> adults should consume 27-40g fibre p/day - dextrin
> dry heat applied to starch - starch browns
> found in toast and brown flour
4
Q
Physical structure of starch
Carbohydrates: amylose and amylopectin
A
- amylose
- chain type molecule
- gelling
- form a firm and stable gel
- amylopectin
- branched molecule
- cohesive properties (thickening) not gel
- waxy starches
corn, rice, sorghum
nongelling properties and no amylose
5
Q
Functions in the body
Carbohydrates
A
- CHO broken down during digestion - various enzymes in mouth, stomach, intestine
- glucose results and absorbed into the bloodtsrem
- glucose not used by heat and energy - stored in the liver and muscles by action of insulin (hormone = produced by pancreas)
- insulin converts glucose into glycogen for storage
- hunger, anger, shock - body requires glycogen for these
- adrenalin (prod. by adrenal glands) is converts glycogen into glucose for the body to use for heat and energy
6
Q
Glyceamic Index (GI)
what it does, low, medium, high
A
- measures how much a food containing carbohydrates will raise levels of glucose in the blood.
- on a scale from 1 - 100
- LOW GI (1-55)
prevent blood sugar from rising too quickly
fruit, veg, oats, whole grain break, oats - MEDIUM GI (56-69)
gradual rise in blood sugar levels
whole grain pasta, potato chips, muesli - HIGH GI (70+)
release glucose quickly + useful when exercising and need energy quickly
white rice, cakes, cereal bars, white bread
7
Q
Functions of carbohydrates
A
- provide energy
- spare proteins - proteins concentrate building, repairing and maintaining body tissues
- fat metabolized properly -> carbs present
- not enough carbs = large amounts pf fat used for energy
- necessary for regulation nerve tissue - only source of energy for brain
- certain types encourage growth of healthy bacteria in intestine for digestion
- some high fibre - prevent constipation and lowers risk for certain diseases
cancer, heart disease, diabetes
8
Q
Deficiency
A
marasmus:
* extensive tissue and muscle wasting
* oedema - fluid retention (ankles)
* dry skin and lose skin folds
* fretful
* irritable
* voraciously hungry
9
Q
Diabetes
A
body doesnt produce sufficient insulin - diabetes mellitus
control amount of carbs eaten
may take insulin injections and exersice regularly - use up excess glucose in bloodstream
10
Q
Diabetes
type 1
A
- ‘Juvenile diabetes’ / insulin-
dependent diabetes - chronic condition = pancrease
produces little to no insulin - hormone needed allows sugar (glucose) to enter cells and produce energy
11
Q
Diabetes
type 2
A
- ‘adult onset’ / noninsulin-dependent diabetes
- chronic condition - body metabolizes sugar (glucose)
11
Q
Diabetes
type 2
A
- ‘adult onset’ / noninsulin-dependent diabetes
- chronic condition - body metabolizes sugar (glucose)
12
Q
Dietary fibre
soluble
A
- filing - delays emptying stomach and helps control weight
- slows down digestion of CHO and helps control blood glucose levels - beneficial for diabetics
- cholestrol lowering effect - reduces risk of coronary heart disease
barley, oats, beans, prunes
13
Q
Dietary fibre
Insoluble
A
- connot be digested by body
- food passes along intestines - fibre absorbs water and increases in bulk
- softens faeces to pass easily along the digestive system and out the body
- fibre passes through body quickly - picks up wast in the intestines and carries through bowels
- promotes peristalsis and prevents constipation
- ‘mops’ up harmful substances from bowels - may be harmful if left
- problems not removing faeces quickly and regularly - constipation, fiverticular disease (muscle spasm in colon), haemorrhoids, cancer of colon
cereals, whole wheat bread, apple, avocado
14
Q
Effect of heat on CHO
Moist
A
- sugar
- dissolves and forms syrup = caramelizes
- heating continued finally form carbon (black) as the water evaporates
- starch
- granuels swell
- mixture thickens and becomes more translucent
- thickening aka gelatinisation
- Cellulose
- softened and becomes more digestable
- overcooking cases it to disintergrate
