use of sensory and objective methods to find out the quality of food products are given in short here

1. QUALITY EVALUATION OF FOOD
PRODUCTS
by
T.TAMIL SELVAN

2. Quality
It is the ultimate criterion for desirability of any product.
Food quality can be evaluated by
1. Sensory methods
2.Objective methods.
Subjective analysis:
Methods of evaluating food quality based on some
measure of perception by human senses.

3. Sensory analysis (or) sensory evaluation.
The quality of food product is assessed by means of
human sensory organs.
Ex: Appearance,flavour,colour,texture.
It is also called Subjective or Organoleptic test.
Three sub-sections:
1.Effective testing
2.Affective testing
3.Perception

4. Effective testing:
deals with objective facts about products.
Affective testing:
Subjective facts such as preferences that is how
well the products are likely to be accepted.
Also called as Consumer testing.
Perception:
Biochemical and psychological aspects of
sensation.

5. OBJECTIVE METHODS
Methods of evaluating food quality that depend on
some measure other than human senses.
Ex: characters like Density, Maturity, Moisture content, Oil
content, Tenderness.
Quality of food product depends on properties such as
1.Physical properties.
2.Mechanical properties.
3.Optical properties.
4.Electrical properties.
5.Magnetic properties.
6.Electro-magnetic properties.

6. Physical properties:
such as size, shape, weight, specific gravity, Bulk
density, volume, porosity,...
 These are easy to understand and perceive
 Easy to determine
 Does not require sophisticated equipment.
Electro - Magnetic properties:
Having visible wavelength of 400-700 nm.

7. Optical Properties:
Appearance gives first impression about the
quality of product.
The optical properties measuring Appearance and
Texture of a material are defined by percentage of incident light
that is reflected, transmitted or absorbed by each wavelength.
Defining of colour is very important during
quality detection .
RGB colour system is used.

8. Acoustic Properties:
Based on acoustic response generated by the
product.
1.Mechanical stroke/Impulse
2.Ultrasound waves.
High power , low frequency ultrasonic excitations used to
determine Fruit tissue properties.
 use to grade fruits and vegetables.
Limitations:
1. Contact between acoustic probe and sample.
2. Affected by surface characters like cracks.

9. Electrical properties:
It depend mainly on their Moisture content and
nature of water held.
Chemically bound water exerts less influence than
free water in which polar molecules can orient freely with applied
electric field.
Limitations:
 Loss of viability
 Electrode should touch the sample

10. Radiological properties:
Electro magnetic spectrum from x-ray to
infrared have been used for various applications.
Ex: Egg sorting,
Apple defect detection,
Real time inspection of citrus.
checking firmness of fruits and vegetables.
Quality measurement of cheese.
Meat, pork grading

11. Thank You...