2.
Sensory evaluation is a scientific discipline that analyses and
measures human response to the composition and nature of
food products.
Sensory Evaluation does not deal with likes and dislikes, ok or
not ok but the process scientifically elicits , measures ,analyses
and interprets physiological response to physical stimuli by a
food products.
It is a scientific discipline perceived by senses of sight , smell,
taste, touch and hearing.
Sensory Evaluation
3.
There are five sense in human being used for sensory
evaluation :
Sight : Ability of eye and brain to detect electromagnetic waves
and interprets image for detection of sensory properties of foods.
Hearing : Senses of sound is perceived by ear using vibrations .
Touch : Senses of pressure perception , texture analysis of food
products using skin.
Taste :The taste buds are present in tongue that identify taste of
food products. Our tongues distinguish between five basic tastes
such as sweet , sour, salty, bitter and umami.
Smell : The sense of smell also called olfactory senses serves to
perceive aromas of different food products using chemo-electrical
transduction.
Human Senses
5.
Training and employees maintenance is very costly issue which
can be overcome by using computer aided sensory evaluation.
This gives accurate measurements as compared to panel
members.
Initial investment and maintenance of computerized sensory
assessment lab will repay in long run in terns of planning,
efficiency and cost effective.
Need for computer aided sensory
evaluation :
6.
There are specially designed hardware and softwares for
sensory evaluation of food products.
Computer have different detectors like colour, texture, E –
Nose, E- tongue, and sound detectors which work similar to
human senses.
Computer aided sensory
evaluation
7.
The electric nose is a device which detect the smells more
effectively than human senses of smell.
It consist of sensor array, pattern reorganization modules, and
headspace sampling to generate signal pattern that are used for
characterizing smells.
An electronic nose consist of mechanism for chemical detection.
It uses an array of gas sensor which are overlapping with a
pattern reorganization component.
When a specific sensor receives the molecules , it transmit the
signals to a program for processing .
E - Nose
8.
Cont…
The electric nose consist of three major components which are
detecting system , computing system and sample delivery
system .
9.
An electronic tongue is an instrument which comprises of
electrochemical cell , sensor array and appropriate pattern
recognition system capable of recognizing non volatiles
materials which forms taste of samples.
The sensor array consist of potentiometric metal based
electrodes .
A taste sensor is composed of several lipid membranes for
transforming information of taste into an electric signal.
The output of electronic tongue shows different pattern for
chemical substance which have different taste qualities .
E - Tongue
11.
TPA is a popular test for determining the textural properties of
foods.
During a TPA test, samples are compressed twice using a
texture analyzer to provide insight into how samples behave
when chewed.
The TPA test is called two bitting test because texture analyzer
mimics the mouth bitting action.
The TPA is an analytical method which can quantify multiple
textural parameters such as hardness , cohesiveness ,
adhesiveness etc.in just one experiment.
Texture profile analysis
12.
Cont…
Fracturability – first significant break in the curve
Hardness – force exhibited in first bite at max compression
Cohesiveness – ratio of positive areas under first and second
compression
Adhesiveness – work required to pull the plunger away after
first compression
Springeness – ratio of length of compression in the 2 and 1
plunge
Stringiness – distance for which product is extended during
decomposition before separation of probe
Gumminess – hardness * cohesiveness
Chewiness – gumminess * springiness
14.
E – eye has proven to give a fast , accurate and cheap
evaluation of food , shape , size, colour and brightness.
The e – eye system is based on different elements light source,
camera, computer with software and high resolution monitor.
Camera is used for capture the image.
LED , halogen , sodium lamps are used as light source.
The characteristics of sample surface can scatter or reflect the
light by which sample evaluation can be done.
Electronic - eye
15.
A biosensor is an analytical device containing an immobilized
biological materials such as enzyme , antibody etc.
Biological materials interact with an analyte and produce
physical , chemical and electrical signals that can be measured.
Biosensor