What is the importance of grains?
- Grains are very versatile - at least one type can be grown almost everywhere.
- High in carb content and are easily stored and prepared
Describe the general structure and composition of a grain.
Bran - outer layer, contains most of the vitamins and minerals
Aleurone - under bran layer, high in protein and phosphorus
Endosperm - centre portion, most of the protein and starch
Germ - small shallow end, most of riboflavin content
Identify the three properties of starch
- raw starch is insoluble in cold water
- cooked starch forms a paste - this differs between the type of starch (eg. corn or potato)
- texture is soft and cohesive
Differences between amylose and amylopectin
amylose: linear polysaccharide, contributes to gelling
amylopectin: highly branched polysaccharide, forms thickening properties
Discuss factors requiring control when cooking starch
- Heating temperature - differ between starch types
- Heating time - heated rapidly so granules swell quickly at high temps
- Stirring intensity - accelerates gelatinization
- pH of the mixture - low pH can decrease viscosity,
- Addition of other ingredients - sugar, fat and protein
Identify five types of wheat flour
Cake Pastry All Purpose Self Raising Strong / Bread making
Explain the classes of wheat
- Hard
- Soft
- Durum
Explain the grades of wheat flour
Graded based on the four streams used to make them
Patent flours divided into: First patent - Second patent - First clear - Second clear - Red dog
Types of flours
- hard wheat
- soft wheat
- wholemeal
- white
What is enriched flour?
White flour with added B vitamins and iron, improves the nutritional status of people
Properties of gluten flour
- comprises of two parts = glutenin & gliadin
- provides elasticity and strength
Other non wheat flours
- cornmeal
- oat flour
- barley flour
- buckwheat flour
- rice flour
What are the 3 categories of rice type?
- short grain
- medium grain
- long grain
Define Value Added Agriculture?
Process that transforms an original raw agricultural commodities form into something new through packaging, processing, cooling/drying, extracting & other processes
What are 3 examples of Value Added Agriculture?
- breakfast cereals (many are ready to serve mixtures with added sweetners)
- baked products (flour liquid, fat, sugar, salt, eggs, leavening agents and flavourings)
- corn refining (corn id converted into starch, oil, protein and fibre)
Name four products derived from corn
Corn oil, feed products for animals, starches, sweetners and alcohol/ chemicals (from fermentation)
What is the role of liquid in a baked product?
- hydrates the protein and starch
- helps with gluten development an dispersion of all colloids
What is the role of fat in a baked product?
- facilitates air incorporation
- tenderises product
What is the role of salt in a baked product?
- adds flavour
- in yeast breads, regulates action of yeast
What is the role of leavening agents in a baked product and what are 4 examples?
- produce gas in batter to make it more light and porous
- Yeast, baking powder, steam and air
What are the general objectives in mixing doughs & batters?
- uniform distribution of ingredients
- optimum blending and development
Define what components are in the following:
whole grain
whole meal
cereals
whole grain - bran + germ
whole meal - bran, no germ
cereals - wheat/rice, no germ
