Week 2

Question 1

The order of preliminary operations

Answer 1

Cleaning, sorting, and grading

Question 2

What is cleaning and its methods

Answer 2

To remove any contaminants in raw materials
Dry cleaning and wet cleaning

Question 3

Dry cleaning methods and its function

Answer 3

Screening: removing contaminants different in size from foods
Aspiration: to exploit the differences in aerodynamic properties of the food and contaminants
Magnetism: removal of ferrous metal using electromagnets
Electricity: to distinguish food of similiar geometry but different in surface charge

Question 4

Benefits of cold water in wet cleaning

Answer 4

To reduce respiration, retard softening

Question 5

Factors affecting the efficiency of wet cleaning

Answer 5

Amount
Temperature
Force applied
Acidity
Minerall content

Question 6

Wet cleaning methods and its function

Answer 6

Conveyor belt with spraying water: used for soft fruit
Rotary washers: made of thin rods or wire mesh
Flotation washers: with water circulation
Brush washers: contain cylindrical rotating brushes

Question 7

Advantages of combo washing machine

Answer 7

Low water consumption
Good washing results
Low operating cost
Dry preliminary soil removal

Question 8

Sorting machine principles based on

Answer 8

Weight, size, shape, color, aero and hydrodynamic

Question 9

Types of sorting and grading equipment

Answer 9

Disc separator (size and shape)
Vibrating screens
Rotating drums
Series-consecutive or parallel-consecutive roller drums (requires large floor area)
Roller sorter
Mechanical color sorting

Question 10

Types of peeling

Answer 10

Abrasive peeler
Lye peeling
Steam peeling