about food engineering

1. Food engineering is a multidisciplinary field of
applied physical sciences which combines science,
microbiology, and engineering education
for food and related industries
Prepared by
Dr. Zubala Yasir Lutfi

2. • Production Manager
• Quality Analyst
• Researcher
• Mechanical Designer of Food plants
CAREER IN FOOD
ENGINEERING

3. Application
Agriculture
GMO
Production
Plant design
Heat and
Cooling
controlling
Food packaging
system

4. • Food production systems
for NASA mission
• Extrusion
• Package sealing methods
and integrity inspection
• Process automation
• Food product shelf life
and quality
• Microencapsulation
• Edible films and costing
RESEARCH IN FOOD
ENGINEERING

5. • A physical change to which material is subjected
especially in coordination with a unit process
• State of egg, changes after beating
UNIT OPERATIONS

6. • Cleaning
• Sorting
• Grading
• Size reduction
• Evaporation
• Drying
• Extraction
• Fluid Flow
• Heat Transfer
• Mixing
UNIT OPERATIONS IN FOOD
INDUSTRY

7. CLEANING
• Cleaning involves the separation of
contaminants from the desired raw
materials.
• Cleaning is an essential preliminary
operation in any food industry.
• The ultimate quality of the finished
product, storage stability,
organoleptic properties, safety
from health hazards, and consumer
acceptance depend on cleaning
process.
• The methods adopted depend on
the type of raw material, type and
extent of contamination, the
degree of cleaning to be achieved
and the type of finished product.

8. TYPES OF CONTAMINANTS
Different food raw materials are associated with
different types of contaminants. These include
• Mineral contaminants- soil, sand, stone metallic
particles, grease and oil.
• plant part- stalks, pits, husks and rope,
• Animal parts and contaminants—excreta, hair, insects
eggs and body part
• Chemical contamination- sprayed residues of
pesticides, insecticides and fertilizers
• Microbial contaminants—microorganisms and their
metabolites.

9. The chosen cleaning process must satisfy the
following requirements in order to achieve
the aforesaid objective:-
• The separation efficiency of the process must
be high and consistent and should produce
minimum wastage of good material
• Damage of cleaned raw material must be
avoided

10. Types of
Cleaning
Dry
Cleaning
Wet
Cleaning

11. DRY CLEANING
1. Screening
Screens are primarily size
separators or sorting machines
but may be used as cleaning
equipment for removing
contaminants of different size
from that of the raw material.
These machines are useful in
cleaning fine materials such as
flour and ground spices but
must be frequently cleaned to
remove oversized contaminants
which may otherwise get
pulverized due to abrasion and
spread contamination of the
raw material.

12. DRY CLEANING
2. Abrasion or Brushing Cleaning.
Abrasion between food particles or
between the food and moving
parts of cleaning machinery is used
to loosen and remove adhering
contaminants.
 Tumblers, vibrators, abrasive discs
and rotating brushes are used for
this purpose.
 This technique is specially used for
heavily contaminated foods such as
potatoes, carrots, radish etc.

13. DRY CLEANING
3. Aspiration Cleaning or Winnowing.
• Aspiration (or winnowing) is based on the
differences in the aerodynamic properties
of materials.
• The raw material to be cleaned is fed into
a stream of air flowing at controlled
velocity to separate the raw materials into
two or more streams (e.g. light and heavy
streams). The cleaned products are usually
discharged as the middle stream leaving
the heavy debris (stones, pieces of metal
or wood) behind while floating off the light
debris such as stalks, husks and hairs.
• This method is used in cleaning cereals,
nuts, beans, onions, melon, eggs etc.

14. Advantages Disadvantages
Production of safe product. Not as flexible
Improved shelf life. Possibility of health and explosion
hazard from dust
Reduction of off flavor, odor and
color.
Increased cost to control dust
To an extent, it could also prevent
equipment deterioration and
increase production efficiency.
Does not add extra moisture to food
Equipment is cheaper and smaller
Cheaper waste disposal
DRY CLEANING

15. WET CLEANING
1. Soaking.
• Soaking is the process of
softening a hard food by
immersing it in liquid, preferably
water, for hours.
• This is the simplest method and
is often used as preliminary
stage in the cleaning of heavily
contaminated root vegetables
and other foods.
• Soaking softens adhering soil.

16. WET CLEANING
2. Spray washing.
• This is the most widely used method for wet cleaning of fruits and
vegetables.
• The surface of the food is subjected to water sprays, The efficiency
of spray washing depends on several parameters such as water
pressure, volume of water, temperature, the distance of the food
from jets, the time of spraying and number of spray jets used.
• A small volume of water at high pressure is the most effective
combination.
• High pressure sprays may be used to cut out parts of peaches and
tomatoes and to remove adherent soil and black moulds on citrus
fruits.
• It may damage ripe fruits and vegetables
• such as straw berries and tomatoes and
delicate vegetables such as asparagus.

17. WET CLEANING
3. Flotation washing.
• The method depends on the differences in buoyancy of the
desired and undesired parts of the food raw material to be
cleaned. For example, bruised or rotten apples sink in water
and can be removed at the base of tank and the good fruit
can be collected as overflow.
• The flotation washer effectively removes stones, dirt and
plant debris from peas, beans, dried fruits and similar
materials.
• Water requirement is about 4,000-10,000 liters per ton of raw
material to be cleaned.
• Froth flotation has been used to separate peas from weed
seeds by immersing the peas in dilute mineral oil-detergent
emulsion through which air is blown, the contaminants float
on foam and are removed. The cleaned peas are given a final
wash to remove the emulsion.

18. Flotation washing

19. WET CLEANING
Advantages Disadvantages
firmly remove adherent soils
and owing the use of
detergents and sanitizers.
use of large amounts of high
quality water
Generation of large volume of
effluent (about 15,000 liters
per ton of canned food).

20. OBJECTIVES OF CLEANING
• Removal of contaminants which constitute a
health hazard or which are aesthetically
unacceptable
• Control of microbiological loads and
biochemical reactions which impair
subsequent process effectiveness and product
quality.