BREAD

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BREAD
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Cereals provide Bread

• Cereals are the Worlds staple
• Provide the majority of carbohydrates as starch
  for the worlds population
• Members of the grass family
• Wheat
• Rice
• Maize
• Oat, Rye Barley, Sorghum

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How are they used?

• Direct consumption
• Rice, Maize, Oats
• Milled for flour
• Wheat, Rice, Maize, Rye
• Milled for starch
• Maize, wheat, rice
• Fermentation substrate
• Barley, Wheat, Rye, Rice, Maize

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Milling

• Grains crushed by a series of rollers
• Remove hull and bran
• Remove germ (embryo)
• Pulverise endosperm
• Wholemeal flour
• Contains bran embryo
• Higher lipid content, rancidity problem

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Mills

• 8,000 BC first grain crops, hand crushing
• 1,500 BC Millstones
• 1,000 BC animal powered mills
• 400 BC watermills
• 1,000 windmills
• 1780 steam power
• 1870 use of steel rollers

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Flour

• Carbohydrate
• Bulk of endosperm, in intact starch granules
• Protein
• Endosperm storage proteins
• Wheat 13 protein
• Glutenin Gliadin
• Lipid
• Mostly removed with embryo

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Types of Flour

• Strong flour
• From hard wheat
• High protein content
• For bread
• Soft flour
• From soft wheats
• Lower protein content
• For cakes biscuits

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Bread

• Dough formation
• Mixture of flour water
• Water uptake depends on protein content
• Kneading
• Developing gluten
• Leavening
• Generation of gas to expand dough
• Baking

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Straight Dough

• Flour water mixture
• Yeast, leavening agent
• Sugar for yeast growth
• Salt for yeast metabolism
• Fat to soften texture, reduce staling.
• Saturated fats better
• 5 in bread 30-50 in cakes
• Milk to improve crumb texture
• Kneading to mix thoroughly
• Develop elastic gluten network

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Proofing

• Incubate 30C 1 to 2h
• Yeast fermentation
• Production of ethanol CO2
• Gas expands dough
• Elastic dough will stretch
• Punching, allows some CO2 to escape
• Moulding shaping

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Cake All-purpose Strong bread
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Alternative leavening agents

• Baking powder
• Acid alkali mix
• Cream of tartar baking soda
• Produces CO2 when heated
• Mechanical
• Beating or creaming to whip in air
• Steam generation
• Whipped egg white

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Baking

• 250 300C, 30 60 min
• Further gas generation
• Dough rises to final shape
• Yeast killed off
• Starch gelatinises
• Gluten coagulates
• Bread becomes hard
• Crust develops and browns

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Sponge Dough

• Moderately stiff dough
• Only 50 of the flour yeast sugar
• Fermented 3 4 hours
• Remaining flour, fats water added
• Finer texture, smaller gas holes

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Batter whipped process

• Chorleywood Process
• Continuous production
• Liquid fermentation with little flour
• Remaining flour added
• Agitated to incorporate air
• Extruded into baking pans
• Fine uniform texture

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Starch

• Starch, main polysaccharide in flour
• Present in starch granules
• Contains 2 polysaccarides
• Amylose amylopectin
• As heat increases
• Starch granules absorb water swell
• Release amylose from granule
• On cooling
• Amylose molecules combine to form gel

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Starch Retrogradation

• Realignment of amylose chains
• Stick to each other more strongly
• Forms more rigid crystalline structure
• Slow process so takes time
• Inhibited by fats that can interact with amylose
• Starch becomes harder

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Staling

• Stale bread old bread
• Harder texture
• Crumb more brittle
• Dryer, poor release of flavour
• Promoted by low temperature
• Regeneration possible by wet heat

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Bread deterioration

• Prone to fungal contamination
• Fungal growth normally prevented in foods by low
  humidity and temperature
• Dry storage at low temp. promotes staling
• Added mould inhibitors common
• Eg. Calcium propionate