Deck 6: Starch

Question 1

The component of starch that facilitates gel formation is:

A) Pectin
B) Amylopectin
C) Amylose
D) Dextrins
E) Maltose

Answer 1

C

Question 2

A colloidal system in which a liquid is dispersed in a solid is called

A) Sol
B) Coagulum
C) Gel
D) Precipitate
E) Gum

Answer 2

C

Question 3

Increasing the amount of sugar in a starch mixture

A) Increases both viscosity and translucency
B) Decreases both viscosity and translucency
C) Has no effect on the viscosity of the cooked product
D) Decreases viscosity and increases translucency
E) Increases viscosity and decreases translucency

Answer 3

D

Question 4

Starch is a complex carbohydrate that consists of two fractions:

A) Amylose and amylopectin
B) Gel and sol
C) Dextrin and dextrose
D) Lignin and hilum
E) Disaccharide and Polysaccharide

Question 5

Amylopectin sub-units are linked together by:

A) 1,4-α-glucosidic linkages
B) 1,6-α-glucosidic linkages
C) Salt bridges
D) 1,4- and 1,6-α-glucosidic linkages
E) Van der Waals forces

Question 6

The amylose content of most starches is approximately:

A) 0-5 %
B) 20-30%
C) 45-50%
D) 75-80%
E) 98%

Question 7

The building blocks of waxy cornstarch are:

A) Fructose
B) Sucrose
C) Glucose
D) Galactose
E) Pectin

Question 8

A thickened starch mixture that flows is called a:

A) Gel
B) Sol
C) Coagulum
D) Precipitate
E) Gum

Question 9

Sugar decreases the viscosity of starch gels by:

A) Competing for water, thus decreasing swelling
B) Diffusing the water out of the gel
C) Fragmenting the starch
D) Hydrolyzing the starch bonds
E) Osmosis causing water to flow from the starch

Question 10

Starch gel formation occurs due to the presence of

A) Amylose
B) Amylopectin
C) Cellulose
D) Modified starch
E) Waxy starch

Question 11

The preferred type of starch to be used in formulating a frozen gelatinized starch mixture is

A) Free amylose
B) Free amylopectin
C) Waxy starch
D) Mealy starch
E) Thin film starch

Question 12

Increasing the amount of sugar in a starch mixture decreases the viscosity of the cooked product because sugar:

A) Competes for the water
B) Raises the coagulation temperature
C) Causes acid hydrolysis
D) Breaks the ring structure of glucose
E) None of these

Question 13

The change that can be observed after a cooked starch mixture has aged for a while is termed

A) Retrogradation
B) Gelatinization
C) Dextrinization
D) Crystallization
E) Aging

Question 14

Amylose sub-units are linked together primarily by:

A) 1,4-α-glucosidic linkages
B) 1,6-α-glucosidic linkages
C) Salt bridges
D) 1,4- and 1,6-α-glucosidic linkages
E) Van der Waals forces

Question 15

To achieve gels of the same gel strength:

A) Always use the same amount of starch
B) Vary the amount of starch, depending on the type of starch
C) Start by dextrinizing the starch
D) Heat all starches to the same final temperature
E) Avoid heating above 60°C.

Question 16

To achieve gels of the same strength, it is necessary to:

A) Use the same amount of any type of starch
B) Vary the amount of starch, depending on the type
C) Dextrinize the starch
D) Heat all starches to the same final temperature
E) Avoid heating above 60°C

Question 17

The amylopectin content of waxy starches is approximately:

A) 5%
B) 20%
C) 50%
D) 75%
E) 98%.

Question 18

Acid is often added to a starch gel after gelatinization because:

A) Acid fragments starch, causing the gel to thin
B) Sugar thins the gel, and acid is needed to thicken
C) The flavor of the acid will be less pronounced
D) None of the above
E) A and C

Question 19

For maximum viscosity of a lemon pie filling, the lemon juice should be added

A) Before stirring in the cornstarch
B) Before cooking the filling
C) Any time while cooking the filling
D) After the filling has started to boil
E) After the filling is removed from the heat

Question 20

The fraction of starch that undergoes retrogradation most readily is

A) Pectin
B) Dextrin
C) Amylopectin
D) Glucose
E) Amylose

Question 21

Gelatinization can occur without producing a product that gels.

Question 22

Amylopectin is responsible for starch gels.

Question 23

Sugar lowers the pH below 4 and fragments and thins starch gels.

Question 24

T or F Arborio rice is an aromatic rice that resists retrogradation in storage

Question 25

Starch usually needs to be gelatinized if gelation of a starch-thickened product is to occur.

Question 26

The effect of acid and of sugar on a gelatinizing starch paste is the same chemically.

Question 27

Waxy and some root starches do not gel.

Question 28

T or F Cereal starches are much more translucent when gelatinized than are potato starch and tapioca.

Question 29

Which of the following is an example of a long grain rice?

A) Mochigomi
B) Calmochi
C) Basmati
D) Arborio
E) Koshihikari

Question 30

An example of a polysaccharide fat replacer is:

A) Tagatose
B) Sucralose
C) N-lite
D) Saccharin
E) Nutrasweet

Question 31

The separation of the liquid from a gel is called

A) Dextrinization,
B) Gelatinization
C) Gelation
D) Retrogradation
E) Syneresis

Question 32

Waxy starches are useful when formulating products with a gel structure.

Question 33

The specific characteristics of starch gels are influenced by the type and concentration of the starch, the extent of heating, agitation, and the presence of

A) Protein
B) Acid and/or sugar
C) Acid and/or salt
D) Sugar and/or amylaise
E) Sugar and/or cellulose

Question 34

Retrogradation is

A) A decreased swelling of the starch granules as sugar competes with starch for water
B) A reforming of hydrogen bonds into crystalline regions as the starch paste is held
C) The breakdown of a starch paste when acid is added at the beginning of the cooking period
D) The swelling of starch granules upon exposure to heat
E) The saturation of the starch granule with an increase of sugar

Question 35

Pasting is the change that occurs to starch if heating is continued after gelatinization has taken place. It includes the loss of amylose and implosion of the starch granule.

Question 36

Acid thins starch pastes because the acid competes with the starch for the water.

Question 37

All starches have the same size and shape when viewed under a microscope.

Question 38

Sugar increases translucency of a gelatinized starch mixture.

Question 39

Retrogradation involves hydrogen bonding of starch molecules into a rigid, irreversible gel.

Question 40

Flour will form a stronger gel than will wheat starch.

Question 41

The food industry is interested in making a chicken pot pie with a thickened sauce. This product would be sold frozen and baked at home in a 400°F. oven. What characteristics of starch would the industry be looking for?

Question 42

Distinguish between:

Question 43

A lemon meringue pie is sliced, in preparation for serving. The filling oozes out of the crust onto the plate. What has caused this? How could it be prevented?

Question 44

Once the pudding and whipped cream were folded together, the filling did not appear to be thick enough to set up when sliced. Why might it thicken later? Should you take
any steps to thicken it now?

Question 45

How do you prepare the to-cook chocolate pudding? List basic steps in preparation.

Question 46

Complete the following chart showing how starch breaks down into glucose.

Question 47

Correct by rewriting the following paragraph of results of the starch paste experiment.

Question 48

Briefly describe the appearance of a cut piece of cherry pie made with corn starch as the thickener compared to a cut piece of cherry pie made with all-purpose flour as the thickener.

Question 49

When tapioca starch pudding is frozen and thawed, it does not undergo syneresis. Why not?
What uses of tapioca does this demonstration bring to mind?

Question 50

A fellow student with this same problem adds one tablespoon cornstarch to the cold pudding/whipped cream mixture. What would this do? What was wrong with this approach? What must happen to the cornstarch for it to thicken? What "side effects" would you see from adding the raw cornstarch?

Question 51

Assuming you had to use the to-cook pudding (no trips to the grocery store!), how would you have proceeded?