Cereals
-Cereals-
Endosperm – starch/protein
Germ - where new plant begins
Bran – outside layer
Strong wheats have high protein content. Weak wheats have less protein
Wheat is milled to make flour.
Wheat flour
Classified according to how much and which parts of grain are used and type of wheat
- % of grain used in flour = extraction (White – 72%, Wholemeal – 80/90%)
- Hard wheat – higher protein content
- Soft wheat produces soft flour – less protein
- All flour contain – 70-80% starch, 2% sugar (maltose)
Quality
- Plain white flours – medium strength. Contain 10% protein (e.g. cakes, biscuits, shortcrust pastry)
- Strong flours - high protein content. (elastic, stretchy dough) (e.g. bread, pasta)
- Granary flour – mix of white and rye flour, whole grains and malt extract added
- Self raising flours – medium soft flours – chemical raising agents added
- Soft/cake flour – low protein content – produces melt in the mouth texture. (e.g biscuits and cakes)
Nutritional Value
- Flour/bread – good source of energy. Supply protein
- NSP/dietary fibre, higher in flour with high extraction rate
Functional Properties
Gluten
- Gluten produced when water added to flour
- Stretches easily
- Fat and sugar reduce strength of gluten
- When heated, gluten stretched by bubbles of gas (produced by e.g. yeast), makes product rise
- Gluten proteins coagulate – produce stable, risen product
Starch
Gelatinization
- 60°C, starch granules between to absorb water
- 85°C, granules absorbed 5X their volume of water
- Granules swell, make a paste – gel
Browning
- As temp. rises, starch turns brown.
Rice
Nutritional Value
- High energy value
- High carbohydrate content
Types
- White rice – bran/germ removed
- Brown rice – outer husk removed
- Easy cook rice – starch partly gelatinized
- Short grain rice – clump together
- Long grain rice – fluffy, firm, separate
Maize
Nutritional Value
- Made up entirely of starch
Used as vegetable, flour and cereals
Cereal
- Milled/processed to produce e.g muesli
- Ground oatmeal – cakes, digestive biscuits etc