Starch

Question 1

Addition of water breaks up amylose crystallinity and

Answer 1

disrupts helices

Question 2

addition of more heat

Answer 2

causes more swelling, amylose begins to diffuse out of granule

Question 3

granules collapsed and held in

Answer 3

a matrix of amylose forming a gel

Question 4

Starch gelatinization is

Answer 4

the collapse (disruption) of molecular
order within the starch granule manifested in irreversible changes in properties

Question 5

in irreversible
changes in properties

Answer 5

granular swelling, native crystalline melting, loss of birefringence, uncoiling and dissociation of the double helices and starch solubilisation

Question 6

Starch gelatinnization (other definition)

Answer 6

Destruction of molecular order and irreversible
swelling of starch granules under the influence of heat and/or chemicals in an aqueous medium to give starch paste

Question 7

In the presence of water, when starch is heated sufficiently

Answer 7

the granule begins to swell

Question 8

Swelling of granule

Answer 8

causes viscosity to increase

Question 9

FACTORS AFFECTING DEGREE OF GELATINIZATION

Answer 9

WATER CONTENT

Question 10

Starch in excess water (>60%)

Answer 10

full gelatinization, with suitable time and
temperature

Question 11

Starch in limited water (<60%)

Answer 11

Partial gelatinization, depending on other factors
(time-temperature

Question 12

Limited water- mechanism of gelatinization

Answer 12

Gelatinization of amylopectin crystalline
happen at higher temperature

Question 13

excess water-mechanism of gelatinzation

Answer 13

-Heat will weaken the hydrogen bonding in amorphous granules, and facilitate the
absorption of water into the granule
-Granule swelling that start from amorphous will destabilized the crystalline region and gelatinization of amylopectin occurred

Question 14

In baked products –

Answer 14

many starch granules remain
ungelatinized

Question 15

In cookies and pie crust (high fat and low water)

Answer 15

about 90% of wheat granules remain ungelatinized

Question 16

• In cake and white bread (high in moisture) –

Answer 16

90% are gelatinized, although many become deformed

Question 17

EFFECT OF OTHER INGREDIENTS; sugar

Answer 17

Very hydrophilic, compete for water with starch, sugar love water

Question 18

Smaller size of sugar bind easier to water
molecules,

Answer 18

less water available for starch granules

Question 19

under effect of sugar

Answer 19

Shifted gelatinization temperature to higher temperature

Question 20

FAT/EMULSIFIER

Answer 20

• Coating effect

Question 21

Formation of amylose-lipid complexes

Answer 21

Bind tightly into the hydrophobic region of the helix, absorb less water

Question 22

fat have Ability to hold amylose

Answer 22

reduce the tendency of
starch to retrograde

Question 23

• Ability of amylose to leach out during
  gelatinization is reduced significantly

Answer 23

shifted gelatinization temperature to higher temperature

Question 24

Swelling Ability

Answer 24

Waxy maize > Potato > Hylon VII WPH

Question 25

Amylose give strength to the granules

Answer 25

hold structure of granule – reinforce effect

Question 26

High amylose starch (Hylon VII)

Answer 26

need more heat, higher pressure, longer time with excess water (>60%)

Question 27

Higher temperature,

Answer 27

shorter time

Question 28

Shear enhance

Answer 28

e starch gelatinization

Question 29

. Heating period –

Answer 29

Gelatinization characteristic of starch

Question 30

Holding period

Answer 30

Stability characteristic of starch, ability to hold viscosity

Question 31

. Cooling period

Answer 31

Retrogradation characteristic of starch

Question 32

Pasting Process is a phenomenon

Answer 32

following gelatinization, in the dissolution of starch.

Question 33

pasting involves

Answer 33

granular swelling (part of gelatinization), exudation of molecular components from granule and finally total disruption of granule

Question 34

t pasting is not exactly separated from gelatinization

Answer 34

but rather continuation of gelatinization

Question 35

Analysis Method

Answer 35

1. Microscopy 2. Rapid Visco Analyzer (RVA) 3. Differential Scanning Colorimeter (DSC)

Question 36

Retrogradation

Answer 36

Phenomenon is which the regular structure of starch molecules, lost during gelatinization, is restored during storage. Amylose molecules rearranging in an orderly fashion and is accompanied by gel hardening

Question 37

When a hot starch is cooled, it generally forms

Answer 37

a viscoelastic, firm and rigid gel or precipitate

Question 38

realigning of starch molecules (amylose) and forming double helixes that then will aggregate

Answer 38

hydrogen bonds break and re-reform into more orderly crystals * starch becomes progressively less soluble

Question 39

Retrogradation Happens far more rapidly with amylose

Answer 39

than amylopectin

Question 40

During retrogradation, amylose associates more easily compared

Answer 40

to amylopectin due to restrictions imposed by the branched structure of the molecules

Question 41

Amylose retrogrades over minutes to hours

Answer 41

while amylopectin over hours to days

Question 42

Factors affecting retrogradation

Answer 42

Size of linear starch molecule, Amylose/amylopectin ratio, Temperature, Interfering molecules

Question 43

Smaller amylose have more tendency than large molecules

Answer 43

to closely associate into “crystal precipitates”

Question 44

More amylose =

Answer 44

more and faster retrogradation

Question 45

* Fatty acids

Answer 45

Form insoluble complex with starch and interfere with retrogradation

Question 46

Emulsifiers/surfactants (both hydrophilic and hydrophobic nature)

Answer 46

Inhibit retrogradation by complexing with helical amylose (Commonly used in dough for bread and other baked goods to increase shelf life)

Question 47

Amylose-amylose bonding

Answer 47

◼ Desirable when forming a gel ◼ Undesirable when syneresis ◼ Undesirable when gel cracks upon standing

Question 48

Retrogradation can expel water

Answer 48

from polymer network

Question 49

Separation of water out of an aging gel

Answer 49

due to the contraction of the gel as gel cools

Question 50

The starch molecules pull together more tightly, the gel network shrink

Answer 50

and the water is push out of the gel.

Question 51

Retrogradation is the cause behind firming of bread

Answer 51

as it cools after baking

Question 52

during baking amylose leeches out and retrogrades almost fully on cooling

Answer 52

positively affects texture by giving an elastic and tender crumb

Question 53

On storage amylopectin branches slowly associate

Answer 53

crumb and bread hardens = STALING

Question 54

Happens faster during refrigeration but is inhibited

Answer 54

during freezing

Question 55

Retrogradation further develop into

Answer 55

resistant starch