food proteins-gluten,soya,eggs-Week 7

Question 1

What is vital wheat

Answer 1

gluten that’s sold in a dried state which is produced industrially from wheat flour by separation and controlled during process.

Question 2

why is vital wheat used

Answer 2

due to its ability to form elastic mass when hydrated water-holding capacity & thermosetting properties

Question 3

what is white flour

Answer 3

just the endosperm of a whole grain (germ & bran removed) - results in loss of vitamins & minerals, its rich in starch and gluten proteins

Question 4

what is wholemeal flour

Answer 4

its 100% nothing added or removed to the whole grain

Question 5

what does the whole grain contain & explain what they contain

Answer 5

-Bran: fibre rich outer layer-contains vitamin B
-Endosperm: middle layer which contain carbohydrates & proteins
-Germ: small nutrient-rich core, contains antioxidants- like vitamin B,E & healthy fats

Question 6

what is the Food science definition of gluten

Answer 6

proteinaceous material prepared as a cohesive, viscoelastic by-product derived from the isolation of starch from wheat flour

Question 7

what is glutens structure

Answer 7

glutenin & gliadins are associated though disulphide bonds, non-covalent, hydrogen bonds & hydrophobic interactions

Gliadin- act as filters & strengthen the structure, doesnt let air out(good for baking)
Glutenin- net like structure

Question 8

what is glutens composition

Answer 8

dry gluten must contain a min of 80% protein
moisture: <10%
Ash(minerals): <2%
Fat: < 2%
Fibre: <1.5%
essential amino acid- lysine is the only one

Question 9

what’s glutens 5 functional & sensory properties

Answer 9

*solubility and water holding capacity
*Viscoelasticity
*Flavour
*Thermosetting

Question 10

explain glutens solubility and water capacity (explain what happens when mixed with water)

Answer 10

-gluten is INSOLUBLE in water due to its bonding
-when mixed with water- gluten proteins rehydrate & form cohesive viscoelastic mass
-this water absorption capacity improves product yield, softness & shelf life

Question 11

explain glutens viscoelasticity/how does it happen

Answer 11

-in a WET state, the proteins form a cohesive, elastic matrix that can stretch & expand but maintaining strength
-this permits GAS RETENTION & CONTROLLED EXPANSION

Question 12

Explain glutens flavour

Answer 12

blending of wheat gluten with other food proteins result in improved flavour
but wheat gluten can suffer off -flavours, like rancidity

Question 13

Explain glutens thermosetting

Answer 13

permanent hardening providing structural rigidity & bite characteristics

Question 14

what are glutens NEW functional properties

Answer 14

1) increase of water solubility for emulsification & foam stabilization: this is done by- a)Deamidation with either acid or alkali treatment, b)Enzymatic hydrolysis of peptide bonds
2) Modification by physical treatments, this is done by: a)Texturization by extrusion: produces a fibrous structure to stimulate meat fibres , b)High pressure: changes gluten to more liquid like

Question 15

what are the uses and applications of wheat gluten

Answer 15

-flour fortification & bakery products: increases protein content
-Breakfast cereals:(e.g cereal ‘special K’ uses heat-dried gluten)
-Pasta & noodles: adding gluten reduces cooking loss & stickiness
-Processed meat, poultry & fish products
-Texturized vegetarian foods(e.g as meat replacement or synthetic cheese)

Question 16

what are the side effects of gluten intolerance

Answer 16

inflammation of the small intestine due to immune response responding incorrectly

Question 17

what are 3 solutions to gluten intolerance

Answer 17

1) main treatment is strict diet- avoiding all products containing gluten
2) use oral enzyme supplements to speed up gastrointestinal breakdown of gluten
3) reduce gliadin immunoreactivity

Question 18

what is the composition of soya protein

Answer 18

β-conglycinin and glycinin

Question 19

what are soya proteins uses and composition

Answer 19

Flour: main application in bakery but also to produce alternatives to animal proteins
concentrate: Bakery and dairy/meat products
isolate: any product to replace/reinforce- fat, fibre and sugar removed

Question 20

what are the 4 functional properties of soy protein

Answer 20

1) High water holding capacity: uses-meat & bakery products
2) Gelation(pasty gels): Use- meat, bakery products, soups, ketchup, sauces
3) Emulsification(Fat binding): uses- meat, bakery products, confectionary
4) Texturization: uses-meat extenders & replacers

Question 21

what are 2 applications for soy protein FLOUR

Answer 21

-water absorption
-texture & tenderizing

Question 22

what are 2 applications for soy protein ISOLATE

Answer 22

-texture modifier for ground meat products
-protein enrichment for foods

Question 23

what are 2 applications for soy protein concentrate

Answer 23

• retention of moisture during reconstitution
• improving the appearance

Question 24

what are 2 examples of the proteins in egg whites that are used for foaming and gelation

Answer 24

lysozyme: 4%- foaming
Ovoalbumin: 54%- gelation

Question 25

what are the percentage difference between the amount of proteins between the egg whites and egg yolk

Answer 25

egg yolk: 36% of protein
egg white: 64% of protein

Question 26

what are the foaming function of egg proteins used for

Answer 26

bread, cakes meringues- its Amphiphilic behaviour to encapsulate & retain air

Question 27

what are the gelation function of egg proteins used for-give examples

Answer 27

acts as a linkage binder with other ingredients: uses for desserts, pudding, protein coagulation when cooked