Cereal processing

Question 1

What is the chemical change in bread?

Answer 1

Foam to sponge

Question 2

What does flour contain?

Answer 2

Protein, undamaged and damaged starch

Question 3

What is the importance of damaged starch and amylase activity?

Answer 3

Support yeast activity

Question 4

Why is high alpha amylase content bad?

Answer 4

Converted to dextrin-like substances causes low WHC and weak and sticky crumb

Question 5

What is the main yeast used in bread?

Answer 5

Saccharomyces cerevisiae

Question 6

What is the role of water?

Answer 6

Dispersion, hydration, gluten formation and gelatinisation

Question 7

What is water taken up by?

Answer 7

Protein
Starch (damaged takes up more)
Fibrous components

Question 8

What is the role of salt in bread?

Answer 8

Flavour
Preservation
Fermentation control
Gluten interactions

Question 9

How does salt effect gluten?

Answer 9

Less salt makes gluten harder to process

Question 10

What is the role of sugar in bread?

Answer 10

Yeast fermentation
Crust colour

Question 11

What is the role of oxidising agents (ascorbic acid) in bread manufacture?

Answer 11

Increase protein cross-links, shorten mixing time and improves gas retention

Question 12

What is the role of reducing agents (cysteine) in bread manufacture?

Answer 12

Break disulphide bonds and weaken structure

Question 13

What is the role of surfactants in bread manufacture?

Answer 13

Improve dough stability

Question 14

Role of fat in bread manufacture?

Answer 14

Improves volume, texture and slicing

Question 15

Why is soya sometimes used in bread making?

Answer 15

Enzyme active with oxidising effect

Question 16

Which process is fat used in?

Answer 16

Chorleywood process

Question 17

What occurs during mixing of bread?

Answer 17

Glutenin and gliadin proteins hydrate to form gluten and gas cells

Question 18

What does kneading do in bread manufacture?

Answer 18

Unfolding and cross-linking of proteins

Question 19

How does bread dough resemble a foam?

Answer 19

Bubbles become trapped in a gluten network

Question 20

What occurs during proving?

Answer 20

Glucose and fructose are fermented to CO2 and alcohol to inflate gas cells

Question 21

What occurs during bread baking?

Answer 21

Increase gas production
Gluten is denatured and coagulated
Transition to sponge (92-96C)

Question 22

How does bread become a sponge?

Answer 22

Cells interconnect and liquid moves through matrix

Question 23

What are the 2 types of bread manufacture?

Answer 23

Bulk fermentation process (fermentation)
Chorley bread process (no fermentation)

Question 24

Why is Chorley bread process the preferred method?

Answer 24

No resting and no emulsifier needed

Question 25

What is the chemical structure of cake?

Answer 25

o/w emulsion with air bubbles in fat phase

Question 26

What is the role of flour in cake batter?

Answer 26

Prevent fat or air cell coalescence

Question 27

What occurs to flour during baking?

Answer 27

Starch granules imbibe, swell and gelatinise

Question 28

What are the leavening agents used in baking?

Answer 28

Alkali Acid

Question 29

What does egg do in cake batter?

Answer 29

Yolk stabilises o/w emulsion and white stabilises air cells

Question 30

What causes foam to sponge transition?

Answer 30

Egg protein gelation and denaturation of protein network

Question 31

What is the role of fat in cake batter?

Answer 31

Air cell stabilisation

Question 32

What occurs to fat as cake is baked?

Answer 32

Disperses through aqueous phase and can prevent moisture loss

Question 33

What is the role of sugar in cakes?

Answer 33

Breaks down fat crystals causing air stabilisation Delays gelatinisation (allows time for aeration)

Question 34

How does sugar prevent gluten formation in cakes?

Answer 34

Competes for water and enhances protein denaturation

Question 35

How does rising occur in puff pastry?

Answer 35

Layers trapping water vapour

Question 36

What occurs during baking of puff pastry?

Answer 36

Water converted to steam Fat behaves as barrier to prevent escape Steam causes layers to separate and lift Melted fat gives soft texture

Question 37

What are the processes in biscuit manufacture?

Answer 37

Ferment Laminate Sheet and cut Moulded Extruded

Question 38

What are the types of biscuit?

Answer 38

Hard developed Short doughs

Question 39

Characteristics of hard developed doughs

Answer 39

High water (loss) Less enriched Gluten Dissolved sugar Shrink

Question 40

Characteristics of short doughs

Answer 40

Low water Enriched Not dissolved sugar No gluten Thick matrix