Gluten Flashcards
outline the components of a whole grain
bran
endosperm
germ
outline the components of a white grain
endosperm
what is the bran?
the fibre rich outer layer that provides protection
what is the endosperm
the middle layer containing carbohydrates and proteins
what is the germ
the core that contains antioxidants and fat
uses of hard white wheat flour
pasta
uses of soft white wheat flour
cake, biscuits
uses of hard red wheat flour
bread
what has to be added to white bread by law
vitamin B1, iron, calcium
what has to be added to wholemeal bread by law
nothing
what is gluten
a proteinaceous material prepared as a cohesive, viscoelastic by-product derived from the isolation of starch from wheat flour
what is vital wheat gluten
gluten in its dried state
it is produced from wheat flour by wet separation and controlled drying
it is an additive in bread manufacture
it retains the original properties of gluten upon rehydration
what is commercial wheat gluten
a cream coloured powder that is mixed with water. to form a cohesive viscoelastic mass
what are the advantages of gluten in the industry
sold at a modest price
what are the disadvantages of gluten in the industry
not high in biological value
not widely researched
has a link to coeliac disease
what is the manufacturing process for gluten powders
mix flour and water to form a dough, allow the dough to rest
once fully hydrated, the gluten protein agglomerates are produced, they are then separated from starch via centrifugation in decanters
they are then dried, ground and sieved to obtain a powder
are gluten proteins hydrophilic or hydrophobic
hydrophobic
what should the composition of protein in dry gluten be based on the Codex standard
must contain at least 80% protein
name the two protein in gluten
Glutenin
Gliadin
what is glutenin
polymeric strands with a high molecular weight, responsible for the elasticity of gluten
what is gliadin
a monomeric molecule responsible for the extensibility and viscosity of gluten acts as a fller 4 types - alpha -beta - gamma -omega
what is the relationship between gluten and its amino acid composition
high content of essential amino acids and high levels of glutamine
outline the structure of gluten
glutenin and gliadins are associated through disulfide bonds, non-covalent hydrogen bonds and hydrophobic interactions- which provide gluten with viscosity, elasticity and extensibility
what are the properties of gluten
solubility and good water holding capacity
- gluten is insoluble in water
- when mixed with water a gel is formed
viscoelasticity
- low content of charged amino acids are linked to a close association and a resistance to dispersion
flavour
- can be blended to improve flavour
- off flavours are caused by rancidity due to lipid oxidation
thermosetting
- permanent hardening improves structural rigidity and bite characteristics
how can the properties of gluten be modified
chemical modifications - increasing water solubility chemically for foam and emulsion stabilisation
- deamination: done with either an acid or alkali, removes the amine group from the amino group
- enzymatic hydrolysis of peptide bonds
physical modifications
- texturisation by extrusion, which produces a fibrous structure to stimulate meat fibres
- high pressure
what are the uses of gluten
milling
flour fortification (improves protein content)
noodles
cereal, processed meat, pet food (acts as a binder)
baking
pasta (reduces stickiness)
what is the name of the disease that causes gluten intolerance
coeliac disease
- inflammation of the small intestine due to a inappropriate immune response to wheat gluten, affecting water and nutrient absorption
- treatment= diet modification
