WEL-COME
May 21, 2015
WEL-COME
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University of Horticultural Sciences, Bagalkot
Principles of sensory evaluation of Essential oils
Presentation on,
Shivanand, M.R.UHS11PGM143Dept. of PMA
KITTUR RANI CHANNAMMA COLLEGE OF HORTICULTURE, ARABHAVI 591 218
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• Quality of any product - acceptance by the consumer
- marketability
• However, it was realized that without sensory evaluation, the
acceptability of a product cannot be determined
• In the past, human sensory perception has been the only means
of evaluation of quality as illustrated by the classical examples
of cooks, who knew, how to mask the off nodes long before
microbial assessment of quality came into existence
The product quality was being traditionally determined by physical,
chemical and microbiological criteria with the assumption that the
products meeting the prescribed specifications in the above parameters
would automatically meet the desired sensory quality
However, soon it was realized that without sensory evaluation, the
acceptability of a product cannot be determined
The sensory evaluation is of great significance as a quality control tool in
the oil processing plant
Sensory analysis maintains the product quality and pattern matching with
the consumer concepts and provides a mean to optimize the product
successfully
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“Sensory analysis is a scientific discipline used to
measure, interpret and analyse reactions to those
characteristics of foods and materials as they are perceived
by the senses of sight, smell, taste, touch and hearing”.
Definition
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To understand the difference between trained and untrained testers
To know which senses are used in sensory evaluation
To understand how sensory tests are used
To know the different tests commonly used in the oil industry
To influence product listings with retailers by presenting
independent research demonstrating that the company has a
greater understanding of their products profile and consumers
To understand how the product performs against competitors
Objectives
The role of sensory evaluation is to….
provide valid and reliable information to R&D,
production, and marketing for management to
make sound business decisions about the
perceived sensory properties of products.
Sensory Evaluation
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Major components of sensory evaluation are:-
The human sense organs (the judges)
Methods of sensory evaluation
The laboratory
Data analysis and interpretation
Components
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Human Senses
Touch
Sight Smell Taste
Hearing
We tend to perceive the attributes of a any item in the following order…..
AppearanceOdor / aroma / fragranceConsistency and textureFlavor (aromatics, chemical feeling, taste)
Sensory Attributes
Sensory Evaluation
There are at least three steps in the process of sensory perception:
Essential oils are perceived by senses individually and processed by brain into total impression of quality
Impression of Flavor
Taste Odor Mouth feel
Trigeminal perception
Flavor
The overall impression of flavor is a combination of taste, odor, mouthfeel, and trigeminal perception
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Types of Panelists
Consumer (untrained)Semi-trained (experienced)Trained (highly experienced)Responses recorded on ballots (scorecards)
Expectations form Panelists
To produce reliable and valid data, the sensory panel
must be treated as a scientific instrument
It is therefore, necessary that panelists are free from
any psychological features and physical conditions
which might affect human judgments
Panelists must have an ability to perform the task and
to repeat their judgments
It is necessary that each panelist must be free from
the following defects:
Taste perception disorders
Odour perception disorders
Color blindness
Denture defects
Allergies
Use of those medications that effect the ability to taste
Sensory ability
Psychological Factors Affecting Sensory Panel
Expectation Error- This occurs when panelists are given too
much information about the samples. Therefore the
panelists should not be informed about the types of
ingredients used in the sensory testing.
Suggestion Error- This occurs when panelists are aware of
reactions of others during the sensory evaluation. This
should be addressed by providing panelists with individual
sensory booths (designed as per the details shown earlier).
Halo Effect- Sometimes panelists evaluate more than one quality
characteristic at a time. They should therefore be trained and
instructed to evaluate each quality parameter separately.
Central Tendency Error- Panellists may choose the mid range to
avoid extremes. All panelists should therefore be advised to
choose the correct scale for each quality characteristic rather than
just selecting the mid range of the scale to avoid extremes.
Order Effect- This may affect the panelists if the sensory samples
are provided in a defined order. All samples to be presented in a
random order with a three digit number assigned to each sample to
avoid the order effect.
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Ballots / Scorecards
• Developed for specific experiment, date, name of
judge
• Listed in order of evaluation
• Descriptive characteristics need careful descriptions
& way to score numerically
• Acceptability
STEPS IN SENSORY EVALUATION
Define overall project objective
Define test objective
Screening the samples
Designing the test (method and judges)
Conducting the test
Analyzing the data
Reporting the results
CONTROLS IN SENSORY EVALUATION
Temperature
Lighting
Atmosphere -smell
Individual booths
Sample selection (identical code dates)
Coding samples (3 digits codes)
Sample preparation
Sample presentation
Subject selection
Guidelines help to improve sensory evaluations:
Please read instructions carefully
Take as much time you need to arrive at your decision
Note a flavor sensations when judging - initial, overall, and
aftertaste
Evaluate samples from left to right, as they face you on the tray
Rinsing your mouth with water between each tasting helps remove
the flavors and “standardizes” your mouth for the next test
When testing between products with strong aftertaste, give
yourself 1-2 minutes between tasting to avoid flavor carryover
Making sounds like groaning, laughing, or talking during the
evaluation may influence others. Please use the form for
recording all your sensations
If you avoid eating, drinking, chewing gum and smoking 1/2
hour before tasting, it will sharpen your ability to taste and
smell
Check your results as they leave to see how you did
It’s a great temptation to share your “taste experience” with
others. Please wait until everyone has tasted, so you can’t bias
their judgement
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Different tests in sensory evaluation
1) Discrimination test
2) Affective test
3) Preference test
a) Paired comparison test
b) Ranking test
c) Hedonic scale test
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Difference between two or more products
The product A is identical to product B
Find two similar products among three samples
The type of panel required for this type of testing
would normally be a trained panel
1) Discrimination test
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Also known as consumer testing, this type of testing is concerned
with obtaining subjective data, or how well products are likely to be
accepted
Usually large (50 or more) panels of untrained personnel are recruited
for this type of testing, although smaller focus groups can be utilised
to gain insights into products
The range of testing can vary from simple comparative testing (e.g.
Which do you prefer, A or B?) to structured questioning regarding the
magnitude of acceptance of individual characteristics (e.g. Please rate
the "fruity aroma": dislike/neither/like)
2) Affective test
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It involves the biochemical and psychological theories relating to human sensations.
a) Paired comparison test –
Two samples – 1) Standard (control)
2) Experimental
b)Ranking test –• Several samples differ on the basis of single characteristics • Rank will be given for similar products
c) Hedonic scale test – • Measure consumer acceptability of the products • Products are scored on a 5 or 9 point scale
3) Preference test
Descriptive analysis - As a major branch of the sensory science,
descriptive analysis is widely used for collecting people's sensory
opinions on an object being food, cosmetics, apparel items, etc
Normally, for descriptive analysis, a minimum of 5 experts is
required, while with respect to naive panelists, this number should
be much bigger
The sensory experiment should be carried out according to
standardized techniques and procedures designed before the
evaluation
After experiments, statistical analysis is often applied to the
interpretation of the sensory results obtained
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Sensory Evaluation Grading System
Category Excellent Very Good
Good Satisfactory Unsatisfactory
Quality Level
Outstanding /Exceptional
Superior/ Very
Correct
Typical Weak/Not at full potential
Faulty / Defective
Grading System
Five grading categories
www.ngfl-cymru.org.uk
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Grading Form
Characteristics & Attributes
Grading CategoriesComment
ExcellentVery Good
Good Satisfactory Unsatisfactory
Appearance & Colour
Aroma
Correctness
Intensity
Quality
Taste
Correctness
Intensity
Finish
Quality
Harmonywww.ngfl-cymru.org.uk
Sensory evaluation of nutmeg seeds essential oil
Characteristics ObservationOdor Turpentine-like or spicy
Odor intensity Strong
Taste pungent and spicy
Color Colorless to pale yellowClarity
clear
Solubility Insoluble in water, soluble in ethanol,
petroleum ether, diethyl ether,
chloroform
Qualitative and Quantitative Analysis
Qualitative testing helps to determine exactly what
individual constituents are present in an essential oil,
and quantitative testing provides information on how
much of each component is present
This is very important because it is well known by
experts that for any given essential oil, here are
several origins and the quality between them varies
tremendously
Physical parameters
If an essential oil sample passes all of the sensory tests, the next
stage is to test the physical parameters of the essential oil by
means of measuring the Specific Gravity, Optical Rotation and
Refractive Index
The combination of these physical tests is usually sufficient to
determine if it is worth proceeding to the final stage of testing an
essential oil
If an oil successfully passes the first two stages it is then tested
using Gas Chromatography/Mass Spectrometry (GC/MS)
Gas chromatography When using Gas Chromatography to test an essential oil, a tiny
sample of the oil is injected (pictured right) into the apparatus
which contains a very thin coiled silica tube called a 'capillary
column'
This capillary column may measure up to 100 meters in length
and is coated on the inside with a material that has an affinity to
different chemicals at different temperatures
The column is housed within a temperature regulated oven and is
programmed to steadily increase in temperature over a period of
time in a very precise manner
When the sample of oil is injected into the column it immediately
vaporises, and an inert carrier gas (usually hydrogen or helium)
moves the vapour along the column to a detector called a Flame
Ionisation Detector which is situated at the end of the column
The flame ioniser detector responds quantitatively to the
vaporised constituents of the oil and converts this information,
via an integrator/computer, into proportional peaks printed onto
computer listing paper. The height of every 'peak‘ on the graph
corresponds proportionally to the level of that component within
the oil
Every individual component of the essential oil can be
identified by the time at which the peak elutes on the
trace. The data produced can then be compared to an
established 'profile' or 'fingerprint' for that particular
essential oil to finally determine the purity of the oil
Adulterants can usually be identified by this means of
testing, although it does require the expertise of an
organic analytical chemist
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Distinguish between the products
Test the popularity of products
Describe specific product attributes
Maintain consistent uniform product quality
Profile the characteristics of a modified product against those of
an original product
Developing new products
Measure shelf life of the product
Industrial applications of sensory evaluation
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Selecting wrong objective for sensory analysis
Choosing wrong participants for the sensory test
Asking wrong questions of the participants
Judgments biased against the products tested
Lacking scientific control
Conducting test in an inadequate situations
Sensory evaluation pitfalls
Thank You