Lab 2

Question 1

What are the 5 primary mechanical characteristics of food?

Answer 1

Hardness
Cohesiveness
Viscosity
Elasticity/Springiness
Adhesivesness

Question 2

Describe hardness

Answer 2

Force necessary to attain a given deformation

Question 3

Descrive cohesiveness

Answer 3

the extent to which a material can be deformed before it ruptures

Question 4

Describe Viscosity

Answer 4

the rate of flow per unit force, the force required to slurp a liquid from a spoon over the tongue

Question 5

Describe elasticity/springiness

Answer 5

there rate at which a deformed material returns to unperformed after the deforming force is removed.

Question 6

Describe Adhesiveness

Answer 6

the work necessary to overcome attractive forces between surface of food and surface of other material.s

Question 7

What are the 3 secondary mechanical characteristics of food?

Answer 7

Fracturability
Chewiness
Gumminess

Question 8

Describe fracturability

Answer 8

the force in which material fractures, such as a food crumbling or cracking or shattering. Is a result of a high degree of hardness and low degree of adhesiveness.

Question 9

Describe Chewiness

Answer 9

energy required to masticate a solid food to a state ready for swallowing. Product of hardness, cohesiveness and elasticity. Is also a producer of hardness, cohesiveness and springiness.

Question 10

Describe Gumminess

Answer 10

the energy required to disintegrate a semi-solid food ready for swallowing. A product of low hardness and high cohesiveness.

Question 11

What factors are considered in the selection of foods to be used as a standard?

Answer 11

1) Major brands of good quality control.
2) Products requiring minimum amount of preparation to eliminate recipe variables.
3) Products that do not change radically with small temperature variation.

Question 12

The evaluation of mechanical characteristics are both _____

Answer 12

qualitative and quantitative.

Question 13

How do standard rating scales work?

Answer 13

• Devised for each mechanical characteristic to provide a quantitate method of texture evaluation.
• Specific examples for each point so proper reference standards are available to measure intensity of each characteristic.
• Reference standards are compared to establish intensity parameter.

Question 14

What are the 3 discriminative (difference) tests?

Answer 14

1) Duo-Trio Test
2) Triangle test
3) Paired comparison test

Question 15

Why do we perform discriminative tests?

Answer 15

to determine whether or not a difference can eb detected between samples.

Question 16

What are discriminative tests useful for?

Answer 16

Detecting sensory variations in food resulting from alterations in ingredients, processing or storage conditions.

Question 17

Explain the Duo Trio Test

Answer 17

Employs three samples, two are the same and one is different.
One sample is designated as the reference,is presented first.
Two coded samples follow .. one is identical the reference.
Panellist is required to identify the sample which is either same or different from the reference, probability is 50%

Question 18

What is the advantage of the duo trio test?

Answer 18

Less tasting required, particular advantage when strong tasting samples are being evaluated.

Question 19

Explain the Triangle test

Answer 19

Employs three samples, two the same and one different. No sample is designated as the reference! Panelist must determine which one of the three samples is different. Probability of choosing the odd same is 1/3.

Question 20

What us the triangle test used for?

Answer 20

Industrial quality control, and also in selecting panelists.

Question 21

Explain the paired comparison test.

Answer 21

Employs two samples. Judge must determine which same has the greatest amount of a particular characteristic. Probability of selecting correct sample is 50%. Ranking test is an extension of this test.

Question 22

Which tests require forced choice?

Answer 22

All 3 of them.

Question 23

Define mechanical characteristics

Answer 23

those related to the reaction of food to stress

Question 24

Define geometrical characteristics

Answer 24

those characteristics related to the arrangement of physical constituents of food.

Question 25

describe “others” characteristics

Answer 25

properties related to the moisture and fat content of foods.

Question 26

List the 2 primary ‘other’ characteristics

Answer 26

• Moisture content

- Fat content

Question 27

List the 2 secondary ‘other’ characteristics

Answer 27

• Oiliness

- Greasiness

Question 28

The fracturability scale is divided in to what three terms ?

Answer 28

1) Crumbly
2) Crunchy
3) Brittle

Question 29

Define crumbly

Answer 29

Samples with low resistance to force (low hardness) and very low deformation before fracturing (low cohesiveness)

Question 30

Define crunchy

Answer 30

samples that have fairly HIGH resistance for force (moderate hardness) and very low deformation before fracturing (low cohesiveness)

Question 31

What the major difference between crumbly and crunchy

Answer 31

crumbly = LOW resistance to force (low hardness)
crunchy = HIGH resistance to force (moderate hardness)

Question 32

What does crumbly and crunchy have in common?

Answer 32

Very low deformation before fracturing (low cohesiveness)

Question 33

Degree is fracturability is measured by what

Answer 33

the horizontal force with which a food moves away from the point where vertical force is applied.

Question 34

How is adhesiveness measured ?

Answer 34

Fore required to remove food from palette with tongue. Influenced by amount of saliva, ensure to rinse with water immediately prior to each evaluation.

Question 35

How is viscosity measured ?

Answer 35

6 point scale, place spoon with standard directly in front of mouth and draw liquid from spoon over tongue by slurping. Degree of viscosity is measured as the force required to draw liquid over the tongue.

Question 36

How is chewiness measured ?

Answer 36

3 point chewiness scales, (tender, chewy and tough), where degree is determined via number of chews to masticate.