Note Tour of Atlantic Superstore in Sydney River TUESDAY 21 MARCH 10:20 AM START, 10:55 AM FINISH

Lecture 21- 28 February 2017 Carbohydrates

Carbohydrates Definition -hydrate of carbon   -hydrate means water -carbon is an element

Carbohydrates Definition -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 digest polysaccharides   -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 fibre fruits- 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  

Note World Health Organisation indicated on 5 March 2014 that keeping one’s simple sugar (mono and disaccharides) consumption to less than 5 % of daily calories (ie less than about 6 teaspoons of sugar) has added health benefits compared to keeping one’s simple sugar (mono and disaccharides) consumption than 10 % of calories. This refers to all simple sugars whether they are added (pop, cakes) or naturally (e.g. honey, fruit) occurring.