Note

Tour of Atlantic Superstore in Sydney River

TUESDAY 22 MARCH,

10:25 AM START, 11 AM FINISH

Lecture 21- 3 March 2016

Carbohydrates

CarbohydratesDefinition

-hydrate of carbon 

-hydrate means water 

-carbon is an element

CarbohydratesDefinition

-literally a carbohydrate then is a hydrate of carbon

 -remember water is H2O

 -thus they contain carbon, hydrogen and oxygen

 

-contain 1 oxygen atom and one carbon atom for every two hydrogens

 -thus overall formula is CH2O

Source

-plants take carbon dioxide from air, water from the soil and energy from the sun to make carbohydrates

Types

-simple, complex

-Types of Carbohydrate

-Simple 

-defined by the way sugar units are linked together

 -sugar units are called saccharides

 -a sugar unit is 6 carbons

(frequently)

Types of Carbohydrate

-Simple

-simple includes monosaccharides and disaccharides -monosaccharides are one sugar unit

-eg glucose (blood sugar) and fructose (fruits and vegetables)

 -disaccharides are two sugar units

-eg sucrose (table sugar) and lactose (milk sugar) and maltose ( occurs when the body digests starch)

 

mono- and disaccharides give varying degree of sweetness to foods

Complex 

-Oligosaccharides

-3-10 sugar units linked together 

-dried beans, peas contain the 2 most common oligosaccharides

Complex  -Oligosaccharides

-body cannot not break down these two most common oligosaccharides on its own so it requires bacterial enzymes that make these 2 oligosaccharides into gas -this explains why one gets gas after eating beans and peas

Complex Polysaccharides

-more than 10 sugar units linked together 

-some are straight chains  -other are branched chains

Polysaccharides

-the way that the sugars units are linked to one another dictates whether the body can digestpolysaccharides

  -we can digest starch but not dietary fibre  - some dietary fibre can be digested by

some bacteria in the large intestine -in the process of such bacterial digestion gas is made

Polysaccharides  -plants store sugars as starch

  -starch comes in two forms -amylose and amylopectin

Polysaccharides

-when we eat plants we eat starch (eg bread or potatoes)

  -animals store sugars as glycogen 

-when an animal is slaughtered glycogen is broken down as part of the death process down so we eat only trivial amounts of glycogen or no glycogen at all

  

Polysaccharides

-dietary fibre provides structure to plant cell walls -all types of plants have dietary fibre including fruits, vegetables, legumes and whole grains 

Polysaccharides

-fibres include -cellulose (long straight chains)

-pectins (found especially in fruits)-pectins mixed with acid give

firmness to jellies and jams 

-gums- used in ice cream to thicken it

Polysaccharides

-fibres are classified as water soluble and water insoluble

-this means that they dissolve in water (water soluble) or that they do not dissolve in water (water insoluble)

 -pectins and gums dissolve in water (water soluble)

 -cellulose does not dissolve in water (water insoluble)

Polysaccharides-foods rich in soluble fibre

fruits- apples, oranges, cranberries 

vegetables-asparagus, broccoli,carrots 

nuts and seeds-pecans, peanuts, walnuts 

legumes-most legumes 

grains-oat bran, oatmeal

Polysaccharides

-foods rich in insoluble fibrefruits- apples, bananas, cherries

 vegetables-sprouts, broccoli, red cabbage

  nuts and seeds-almonds, sesame seeds,

walnuts 

legumes-most legumes 

grains-brown rice, whole wheat breads

Digestion- breaking down foods and their nutrients in digestive tract -eg carbohydrates

Absorption- moving nutrients across intestinal wall -eg carbohydrates

Transport-moving nutrients around in body -eg carbohydrates