Sensory evaluation of essential oils..................

1. WEL-COME

2. Presentation on,
Principles of sensory evaluation of Essential oils
Shivanand, M.R.
UHS11PGM143
Dept. of PMA
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KITTUR RANI CHANNAMMA COLLEGE OF HORTICULTURE, ARABHAVI 591 218

3. • 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
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4.  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

5. “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”.
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6. Objectives
 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
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7. Sensory Evaluation
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.

8. Components
Major components of sensory evaluation are:-
The human sense organs (the judges)
Methods of sensory evaluation
The laboratory
Data analysis and interpretation
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9. Human Senses
Sight Smell Taste
Hearing
Touch
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10. Sensory Attributes
We tend to perceive the attributes of a
any item in the following order…..
Appearance
Odor / aroma / fragrance
Consistency and texture
Flavor (aromatics, chemical feeling, taste)

11. Sensory Evaluation
There are at least three steps in the process of sensory
perception:

13. Essential oils are perceived by senses individually and
processed by brain into total impression of quality

15. Impression of Flavor
Flavor
Mouth Trigeminal
Taste Odor feel perception
The overall impression of flavor is a combination of taste, odor,
mouthfeel, and trigeminal perception

16. Types of Panelists
Consumer (untrained)
Semi-trained (experienced)
Trained (highly experienced)
Responses recorded on ballots (scorecards)
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17. 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

18. Sensory ability
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

19. 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).

20. 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.

21. 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
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22. 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

23. 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

25. 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

26. 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

27. 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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28. 1) Discrimination test
 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
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29. 2) Affective test
 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)
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30. 3) Preference test
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
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31.  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

32. Sensory EvaluationSystem
Grading Grading
System
Five grading categories
Category Excellent Very Good Satisfactory Unsatisfactory
Good
Quality Outstanding Superior/ Typical Weak/Not at Faulty /
Level /Exceptional Very full potential Defective
Correct
www.ngfl-cymru.org.uk
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33. Grading Form
Characteristics Grading Categories
Comment
& Attributes Excellent
Very
Good Satisfactory Unsatisfactory
Good
Appearance & Colour
Correctness
Aroma Intensity
Quality
Correctness
Intensity
Taste
Finish
Quality
Harmony
www.ngfl-cymru.org.uk 33

34. Sensory evaluation of nutmeg seeds essential oil
Characteristics Observation
Odor Turpentine-like or spicy
Odor intensity Strong
pungent and spicy
Taste
Color Colorless to pale yellow
Clarity clear
Insoluble in water, soluble in ethanol,
Solubility
petroleum ether, diethyl ether,
chloroform

35. 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

36. 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)

37. 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

38.  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

39.  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

40. Industrial applications of sensory evaluation
 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
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41. Sensory evaluation pitfalls
 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
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42. Thank You