what are they made up of
CHO
what does cho stand for
carbon, hydrogen, oxygen
another name for dietary fibre
non-starch polysaccharide
dietary energy
sugar: gives sweetness
starch: doesn’t taste like anything
dietary fibre: another type of carbohydrate
where can glucose be found
ripe fruits and some vegetables
powdered liquids or tablet form to provide a fast source of energy
(- converted into glucose during digestion)
fructose
found in fruit, juices + honey
galactose
found in the milk of mammals
form part of the milk sugar lactose
sucrose
glucose + fructose
use for sucrose
commonly used in cookery
is the type of sugar that can be added to tea or used in cake
maltose
glucose + glucose
alternative name for maltose
malt sugar
where is maltose found
cereals such as barley (where it is formed during germination)
lactose
glucose + glucose
where is lactose found
found in milk (is not as sweet as sucrose)
polysaccharids
made up of many monosaccharide molecules (typically glucose) joined together
they are insoluble in water and normally tasteless
what do polysaccharides include
starch, pectin, dextrin, cellulose, glycogen
dextrinisation
can only happen when there is starch and dry heat.
is the breaking up of starch molecules to smaller groups of glucose molecules
when foods containing starch are heated (without the presence of water), they can also produce water compounds known as dextrin
when does dextrinisation occur
when the heat breaks the large polysacchardies known as dextrin
these dextrins can also product a brown colour
example of dextrinisation
toast
gelatinisation
when mixed with water, starch granules swell and eventually rupture, absorbing liquid which will thicken the mixture
when cooled, if enough starch is used, a gel with form
this process is used in the production of blancmange
key temperatures for starch molecules
60ºC: when the starch molecules swell from absorbing the liquid
62º-80º: when the starch molecules burst from being so swollen and the starch properly combines with the water/liquid used
100º: when the sauce becomes completely thickened
what happens when a sauce isn’t constantly stirred
a sauce has to be constantly stirred, if it isn’t, the starch will fall to the bottom and won’t combine properly with the liquid, the sauce will also end up burning
caramelisation
when sucrose (table sugar) is heated above its melting point and undergoes physical and chemical changes to produce caramel
this process can happen to natural products since they have glucose in it
can caramelisation happen without water
yes, the process can happen more readily without water
the syrup will caramelise with rapid heating
this process is used extensively in the production of confectionery
what happens if the caramel is overheated
overheating will cause the substance to become bitter, dark and burnt
why is caramel added to foods
to enhance a either bitter or sweet taste
what will happen is caramel is mixed too quickly when being formed
sugar crystals will begin to form