Personal)Preferences)throughSensory)Evaluation ... · ! 4!...
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1 Personal Preferences through Sensory Evaluation: A Detailed Study of Perception, Association, and Difference Rebecca DeHamer April 16, 2012 NUTR 205L, Section 1 Introduction to the Science of Food
Transcript of Personal)Preferences)throughSensory)Evaluation ... · ! 4!...
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Personal Preferences through Sensory Evaluation: A Detailed Study of Perception, Association,
and Difference Rebecca DeHamer April 16, 2012 NUTR 205L, Section 1 Introduction to the Science of Food
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Abstract The decision to purchase one brand of product over another of the same product is based on multiple factors, one being the preferences and opinions of each consumer’s sensory perception. The purpose of the sensory evaluation lab was to teach students about the process of making impartial conclusions during a sensory tests based on given methods and characteristics. Results of description and associations of the food samples were gathered from forty-‐three student panelists in a San Diego State University food laboratory setting from an Introduction to Science of Food course. The panelist evaluations included: the color of beverages based on a five-‐point scale, difference tests using samples of apple juice with varying degrees of citric acid, a paired comparison test, a triangle test, a scoring test, and a ranking test. Participation also included: a duo trio test using Nabisco Nilla Wafers and Safeway Vanilla Wafers, and a series of descriptive tests for appearance, flavor, texture, aroma, and consistency of goldfish crackers, raisins, almonds, and marshmallows individually. Results revealed beverage associations of sweetness, sourness, and naturalness with yellow coloring, and artificiality with emerald coloring. Panelists were able to accurately differentiate between sample mixtures of apple juice with varying degrees of citric acid, and most preferred the pure apple juice without any added citric acid. Overall, the students were able to make objective evaluations throughout the lab procedures allowing thorough experimental data collection.
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Introduction
The decision to purchase one brand of product over another, is based on
multiple factors, including: the preferences and opinions of each consumer’s
sensory perception. Food manufacturers spend large sums of money every year
testing and analyzing data to promote sales and progress of their company.
Human subject sensory evaluation tests are used in research and development
departments to generate and evaluate products on an on-‐going basis. Objectivity
remains a key question due to the necessity of such human subjects, maintaining
their classification as subjective tests. Sensory tests are broken down into two
categories of affective tests and analytical tests. Affective tests focus on
consumer preference in specific aspects of food testing. Analytical tests
emphasize the objectivity through further categorizing as discriminative (are
samples different), and descriptive (how the samples are different) tests.
Examples of discriminative tests include: triangle, duo-‐trio, paired comparison,
and ranking tests. Triangle tests offer three samples, requiring identification of
which sample is specifically different out of the three. A duo-‐trio test presents
three samples (one set as a standard), asking the panelist to find which sample is
the same as that standard. A paired comparison test offers two samples and asks
which has more of a known characteristic. A ranking test presents multiple
samples and requires the panelist to rank from lowest to highest of the
characteristic that is given (Brown 2010). When carrying out these tests, taste
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panel instructors must be strict on test presentation and panelist’s pallet before
and during testing, in order to get the most reliable sensory results.
Color is a major visual factor in the decision process of food consumption.
In a series of experimental sensory tests conducted by Sandra et al. in 2004,
color was one of the sensory factors effecting the evaluation of crumbling cheese
samples. These researchers found a negative correlation reported by their
panelists from the change in natural color pallet for each cheese sample.
Consumers have parameters for color trends among different food products.
Food companies adhere to these trends for successful growth and sales of their
products in the market. Beverages, often being displayed in clear containers, can
be associated with color parameters as well. Vision is the first sensory evaluating
process used to gather perceptions about the food product or beverage being
presented (Brown 2010).
In a study conducted by Shankar et al. in 2010, subjects were asked to
identify a beverage after using the senses of taste and smell as evaluation factors.
Color remained a strong sensory tool for the participants as they provided data
that correlated flavors of Orange and Grape with corresponding colors. Even
when instructed to ignore color cues, participants relied on color when taste and
smell differences were miniscule (Shankar 2010).
Texture can be equally vital in the process of evaluating food products.
Food companies focus on particular pleasing textures specific to each food
product through sensory testing data. Consumers have strong associations with
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textures that may represent specific food freshness, healthiness, richness, and or
quality (Brown 2010). In a study by Ioannides et al. in 2009, subject’s sensory
sensitivity and reliability of texture was found to be as good as
electromyography (EMG) of the masticatory muscles’ sensitivity and
repeatability. Repeated trials showed sensory results that matched subjects
reporting of texture with the data collected from the EMG. The simple memory of
known texture was as strong as the results gathered from the muscle sensitivity
data when chewing. These results aide in the explanation towards the
importance of food sensations such as texture, consistency, and mouthfeel.
Although these senses are strong and show sensitivity to change, they
have also been shown to be widely variable and subjective. In a study by Marzec
et al. in 2010, varying degrees and temperatures evaluated the textures of dried
apples. Panelists evaluated each apple type, based on overall quality, taste, odor,
hardness, and color. Data revealed that textural preferences of the apple food
products differed greatly from subject to subject (Marzec et al. 2010). Consumer
preferences cannot always be predicted to follow known patterns of group liking
and should remain one of the wonderful individualities known to humans.
In order to examine these parameters, sensory evaluations can be carried
out by a variety of tests. Objectivity and subjectivity remain important factors in
the choosing of each for specific experimental parameters. A variety of tests
were used within this analysis, including the Triangle test, which was specifically
examined on its’ ability to be used as such in a study by McClure et al. 2010.
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McClure et al. found that the Triangle test was effective in this parameter to
indicate consumer preference through discrimination testing. Tests like this can
guide Food manufacturers towards the wants and needs of their consumers
when used appropriately, with data collected from solid sensory testing
methods.
The purpose of this sensory evaluation lab was to teach the student
participants how to evaluate foods objectively based on determined features
using descriptive terms and various taste testing processes. At the end of the
sensory evaluation lab, the student panelists have studied how to properly
conduct a series of sensory tests and can proceed in these evaluation methods
with future work. Students learned how to evaluate the color of the beverage and
how this effects the judgment perception of that beverage. The participants
learned how to evaluate foods based on appearance, flavor, texture, aroma, and
consistency. The subjects also experienced identifying differences in samples
with or without a standard sample for comparison. Finally, the panelists learned
to rank food samples in an order of intensity and preference. This sensory
evaluation lab included a beverage color association test, a paired comparison
test, a triangle test, a scoring test, a ranking test, a duo-‐trio test, and a descriptive
test.
Methods
Panelists
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The panelists were asked to answer an eight point Demographic
Questionnaire. Please refer to the appendix concerning the specific content for
all questionnaires discussed in this manuscript, if not specified already to do so.
All questionnaires used in this evaluation were filled out by a single individual
panelist and recorded as such through collection and the raising of hands by an
individual Teacher’s assistant not included in the panelist pool. The panelists
consisted of 43 untrained SDSU students enrolled in the Introduction to the
Science of Food nutrition class. All of the panelists were nutrition majors. 21 of
the panelists performed the methods at a 9:00 a.m. meeting, and the remaining
22 performed the methods at 1:00 p.m. The ages of the panelists ranged from 19
years old to 43 years old, with a mean age of 22.8 and a standard deviation of
3.87. The majority of the panelists were female, 88%, and only 12% were male.
For student status, 86% were undergraduates, 14% were graduate students. For
marital status, 88% were never married, 9% were married, and 2% were
divorced. For living arrangements, 5% were living alone, 28% were living with
one roommate, and 67% were living with two or more roommates. Concerning
allergies, 88% did not identify with, and 12% did identify with. Additionally,
98% were nonsmokers, and 2% were smokers.
Environment
The evaluation of the Standards of Identity and Standards of Reasonable
Quality for fruit cocktail took place at San Diego State University’s food science
lab room (West Commons 203). All procedures were conducted under
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reasonably controlled conditions (light control, humidity, and temperature).
Lighting was a constant dim, sufficient for working conditions; humidity and
temperature were within a normal range (40-‐45% and 20-‐24°C). The room set-‐
up had standard academic seating arrangements (individual desk-‐chairs) with 5
rows of 6 in the center surrounded by kitchen lab equipment. On two sides of the
desk arrangement were sets of stove top-‐tables (3 per side) housing two per
table. In addition, were 3 sinks per side for hand washing, food washing, and
dishwashing, accordingly. At the front of the room was a corner dedicated to
ovens, housing 6 convection-‐stacked 2 per unit-‐all below a ventilation structure.
At the center of the front and rear of the room are larger desks for instruction
and multi-‐use. Cabinetry surrounds the whole room for storage. The lab room
has no windows, but two doors located at the front corners. Doors were kept
shut during the procedure.
Color Association/Beverage Perception
The panelists were presented with five different beverages of varying
colors and were asked to rank for certain parameters. Each participant recorded
his or her results on the Sensory Testing Beverage Questionnaire (see
Appendix). The drink color was the only ranking evaluation characteristic. The
test was ranked on a 5-‐point scale, with five being the most, four being almost
the most, three being in the middle, two being almost least, and one being the
least. The colors consisted of light yellow, dark yellow, chartreuse, dark
chartreuse, and emerald green placed right to left, respectively at the front of the
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room in uniform beaters. The panelists gave each beverage a rating of 1-‐5 for the
perceived sweetness, sourness, artificiality, naturalness, and which drink the
student preferred or disliked the most. In addition to rating, the participants
were asked to record preferred temperature of the beverage as hot, war, tepid,
or cold. Lastly, the panelists recorded whether or not they would drink the
beverages. The information logged by the subjects on the Sensory Testing
Beverage Questionnaire was tallied and compiled by the lab instructor and
assistant using a show-‐of-‐hands method.
Difference Tests
The panelists conducted a series of difference tests, including a paired
comparison test, a triangle test, a scoring test, a ranking test, and a duo-‐trio test.
The paired comparison, triangle, scoring and ranking tests used samples of pure
apple juice and mixtures of apple juice with added citric acid. The duo-‐trio test
was conducted using vanilla wafer cookies. All of the products were served in
small, white, uniform soufflé cups and panelists tasted each food individually.
Water was available for the panelists to cleanse their pallet, and was served in
white Styrofoam cups. Panelists recorded their evaluation on Sensory Evaluation
Duo-‐Trio Test and Scoring or Rating Test sheet (see Appendix).
The paired comparison test measured which sample of apple juice was
the sourest. The Panelists tasted two samples labeled: 635T1 and 573T2. All
participants walked to the front of the lab to take small samples and refrained
from taking the sample until all participants had theirs to partake together. They
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recorded their perceived results on the Paired Comparison Test table, located in
the Nutrition 205 lab manual (see Appendix). The sample coded 635T1 was pure
apple juice and the sample coded 573T2 was a mixture of apple juice and 1%
citric acid. For the triangle test, panelists identified which two samples of apple
juice were alike and which were different. The samples were labeled: 777C1,
542E2, and 112H9. Students recorded their results on the Triangle Test table in
the Nutrition 205 lab manual (see Appendix). Samples 777C1 and 542E2 were
both pure apple juice. Sample 112H9 was different from the others, containing a
mixture of apple juice and 1% citric acid.
For the scoring test, panelists were given three samples of apple juice to
taste. There was one reference sample, labeled 0110. This sample was given a
ranking score of 4 on a 1-‐7 scale, with 1 being the sourest, and 7 being the
sweetest. Samples 420M and S723 were unknown to the panelists who had to
place them on the scale by their taste interpretation. The participants recorded
their ranking son the Sensory Evaluation sheet (Appendix B). The reference
sample (0110) had 2.5% citric acid, the unknown sample (420M) had 1% citric
acid, and the unknown sample (S723) had 5% citric acid.
In the ranking test, the panelists were given five samples of apple juice.
They ranked the five samples in order of intensity based on sourness; 1 as the
sourest and 5 as the least sour. The participants ranked the samples in order of
preference, following the same scale. The results were recorded on the Ranking
Test table in the Nutrition 205 lab manual (see Appendix). Sample 495P2 was
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pure apple juice, 543K8 had 1% citric acid, 695F8 had 2.5% citric acid, 192L3
had 5% citric acid, and 555D7 had 10% citric acid.
Panelists were presented with three vanilla wafer cookies during the duo-‐
trio test. Sample 8175 was set as the standard as Nabisco Nilla Wafers. The
panelists tasted samples 6104 and 1108, and recorded which vanilla wafer
differed from the standard and why. Sample 1108 was the same as the standard,
and 6104 was the Safeway brand vanilla wafers. The panelists recorded their
findings on the sensory evaluation sheet (see Appendix).
Descriptive Tests
The descriptive tests required the panelists to evaluate four different food
products using descriptive terms. Each sample was evaluated based on its
appearance, aroma, flavor, texture, and consistency. The students were given 2-‐3
bites of marshmallows, raisins, goldfish crackers, and almonds that were all
presented in uniform, white, soufflé cups. The panelists were provided with a list
of descriptive terms that they were allowed to use for each characteristics (see
Appendix).
Statistical Analysis
The course instructor and lab assistant recorded the results of each test
from all of the participants. They were able to record the beverage color and
association test, scoring test, ranking test, descriptive test, paired comparison,
triangle, and duo-‐trio tests using a show-‐of-‐hands method as well as
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questionnaire techniques. All of this data was entered and compiled into an excel
spreadsheet. The results from the two sections were combined.
Results
Color Association /Beverage Perception
All the panelists participated in beverage association activity. When asked
which beverage they thought was the sweetest, 37.2% of the panelists recorded
light yellow, 30.2% dark yellow, 18.6% emerald, 7% dark chartreuse, and 2.3%
chartreuse (Figure 1).
Twenty-‐eight percent of the panelists found the light yellow beverage was
the sourest, 25.6% dark chartreuse, 16.3% dark yellow, 14% chartreuse, and
11.6% emerald (Figure 2).
37.2%
30.2%
2.3% 7.0%
18.6%
Fg. 1 -‐ Sweetest Beverage
Light Yellow
Dark Yellow
Chartreuse
Dark Chartreuse
Emerald
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Seventy-‐seven percent of the panelists recorded the emerald beverage as
most artificial looking, 11.6% dark yellow, and 2.3% each as chartreuse, dark
chartreuse, and light yellow. Eighty-‐eight and a half percent of the panelists
found the light yellow beverage to be most natural, 4.7% found emerald as such,
and 2.3% found chartreuse as such. Sixty-‐seven and a half percent of panelists
had a preference for the light yellow beverage, 11.6% for chartreuse, 7% dark
yellow, and 4.7% for the dark chartreuse and emerald. Sixty and a half percent
of the panelists found most dislike in the emerald beverage, 18.6% with the dark
yellow, 7% with the dark chartreuse and the light yellow, and 2.3% the
chartreuse (Figure 3).
27.9%
16.3% 14.0%
25.6%
11.6%
Fg. 2 -‐Sourest Beverage
Light Yellow
Dark Yellow
Chartreuse
Dark Chartreuse
Emerald
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Fg. 3-‐Most Artificial, Natural, Preferred and Disliked of Beverages
The panelists preferred all the beverages at varying temperatures. In regards to
the light yellow beverage, 95.3% favored it cold, 11.6% tepid. In regards to the
dark yellow beverage, 95.3% favored it cold, 7% tepid, and 2.3% hot. In regards
to the chartreuse and dark chartreuse colored beverage, 95.3% favored it cold,
and 2.3% warm. Lastly, 95.3% of the panelists favored the emerald colored
beverage at a temperature of cold, and 2.3% hot (Figure 4).
2.3%
88.4%
67.4%
7.0%
11.6%
0.0%
7.0%
18.6%
2.3% 2.3%
11.6%
2.3%2.3%0.0%
4.7%7.0%
76.7%
4.7% 4.7%
60.5%
0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
60.0%
70.0%
80.0%
90.0%
100.0%
most artificial most natural most prefer most dislike
Light YellowDark YellowChartreuseDark ChartreuseEmerald
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Fg. 4-‐Preferred Temperature of Beverages
When asked if they would drink the beverages, 81.4% of the panelists would
consume the light yellow beverage, 58.1% the chartreuse, , 46.5% the dark
yellow, 37.2% the dark chartreuse, and 25.6% the emerald beverage (Figure 5).
2.3%
2.3% 2.3% 2.3%
11.6%
7.0%
82%
84%
86%
88%
90%
92%
94%
96%
98%
100%
Light Yellow
Dark Yellow Chartreuse Dark Chartreuse
Emerald
tepid
warm
hot
cold
81.4%
46.5% 58.1%
37.2%
25.6%
Fg. 5 -‐ Drink Beverage = "Yes"
Light Yellow
Dark Yellow
Chartreuse
Dark Chartreuse
Emerald
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Paired Comparison Test
One hundred percent of the panelists who participated in the paired
comparison test identified the mixture of apple juice with 1% citric acid to be
sourer than the pure apple juice.
Triangle Test
Ninety-‐five percent of panelists who participated in the triangle test
identified the mixture of apple juice and 1% citric acid as being different from
the two samples of pure apple juice.
Ranking Test
The 43 panelists who participated were required to put the samples in
order of sourness. Ninety percent ranked the mixture of apple juice with 10%
citric acid as the sourest and 9.3% ranked the mixture of apple juice with 5%
citric acid as such. Ninety-‐five percent of the subjects ranked the pure apple juice
as the least sour, and 4.7% ranked the mixture of apple juice with 1% citric acid
as such (Table 1).
Table 1. Ranking Test: Degree of Astringency showing % of panelists for extreme values % of Citric Acid in Apple Juice
Degree of
Astringency
0%
495P2
1%
543K8
2.5%
695F8
5%
192L3
10%
555D7
1: MOST SOUR 0% 0% 0% 9.3% 90.7%
5: LEAST SOUR 95.3% 4.7% 0% 0% 0%
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Panelists were also asked which sample they preferred the most and the
least. Sixty-‐five and a half percent preferred the pure apple juice overall, 20.9%
the mixture with apple juice with 5% citric acid, 9.3% the mixture of apple juice
with 2.5% citric acid, 7% the mixture of apple juice with 1% citric acid, and 2.3%
the mixture of apple juice with 10% (Table 2).
Table 2. Ranking Test: Degree of Preference showing % of panelists for extreme values % of Citric Acid in Apple Juice
Degree of
Astringency
0%
495P2
1%
543K8
2.5%
695F8
5%
192L3
10%
555D7
1: MOST
PREFERRED
60.6% 7% 9.3% 20.9% 2.3%
5: LEAST
PREFERRED
2.3% 11.6% 2.3% 4.7% 79.1%
Duo-‐Trio Test
Ninety-‐seven percent of the panelists chose the Safeway Vanilla Wafers as
the sample that was different in the duo-‐trio test. They had various reasons for
making their decisions including: 26.2% judged them as stale in comparison to
the other, 14.3% judged them harder in texture than the Nabisco Nilla Wafers
and having different taste, 11.9% judged them as less crunchy, and varying
other reasons (Figure 6).
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Scoring Test
Forty-‐three panelists participated in the scoring test. The mixture of apple
juice with 5% citric acid scored 1 with 58.1% of the subjects, and 2 with 41.9%.
The mixture of apple juice with 1% citric acid scored 2 and 4 each with 2.3% of
the subjects, 5 with 11.6%, 6 with 62.8%, and 7 with 20.9% of the subjects.
Descriptive Tests
The panelists had to evaluate the taste of goldfish crackers, raisins,
almonds, and marshmallows on the characteristics of flavor, texture, aroma,
consistency, and mouthfeel. They further assessed their appearance via a list of
descriptive terms (Appendix). All 42 panelists participated in the goldfish
cracker descriptive test. Thirty-‐one percent of the participants described the
cracker’s appearance as golden-‐brown, 26% as dry, 9.5% each rough and
rounded, 7.1% each symmetrical and as asymmetrical, 4.8% grainy, and 2.4%
0.0% 5.0% 10.0% 15.0% 20.0% 25.0% 30.0%
dryness
less vanilla
stale
texture
ilaky
hollow
Sweet
0.0% 11.9%
7.1% 0.0%
26.2% 14.3%
9.5% 7.1%
2.4% 14.3%
2.4% 0.0%
4.8%
Fg. 6 -‐ 97.6% of Participants chose Safeway based on these characterists
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each puffy and dull. One hundred percent of the panelists described the flavor as
salty. Fifty percent of the participants portrayed the texture as crunchy, 43% as
crisp, and 2.4% each as hard, gritty, and mealy. Seventy-‐eight and a half percent
of the panelists described the aroma as flavery, 9.5% as spicy, 7.1% had no
aroma, and 4.8% as sweet. Sixty-‐six and a half percent of the participants
designated the consistency as cheesy, 23.8% as thin, 7.1% as thick, and 2.4% as
viscous. Sixty-‐eight percent of the panelists found the mouthfeel of the crackers
as crunchy, 18.2% as crisp, and 13.6 gritty.
All 42 panelists participated in the raisin descriptive test. Thirty-‐six
percent of the panelists described the raisin’s appearance as dry, 29% as rough,
9.5% each asymmetrical and dark, 7.15 as smooth, 4.8% as sticky, and 2.4% each
dull and puffy. Fifty-‐two percent of the participants designated the flavor as
sweet, 33.3% as fruity, 9.5% as bitter, and 2.4% each as pasty and musky. Forty
percent of the panelists portrayed the texture as chewy, 24% as gummy, 14% as
gritty, 9.5% as lumpy, 4.8% rubbery, and 2.4% each as rough, firm, and crunchy.
Seventy-‐four percent of the participants reported the aroma as fruity, 21.4% as
sweet, and 2.4% each of flavory and sour. Sixty-‐four percent of the participants
described the consistency as gummy, 16.7% as rubbery, 11.9 as thin, and 7.1% as
thick. Fifty-‐nine percent of the participants found the mouthfeel to be sticky,
22.7% as gritty, 9.1% as slimy, and 4.5% each as crisp and smooth.
Only 41 panelists participated in the almond descriptive test. Thirty-‐two
percent of the panelists described the almond’s appearance as golden-‐brown,
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17% as dry, 15% as light brown, 9.8% as rough, 4.9% each as rounded, smooth,
dull, and grainy, and 2.4% as sticky, symmetrical, and asymmetrical. Eighty-‐eight
percent of the participants designated the flavor as nutty, 9.8% as flat, and 2.4%
as sweet. Forty-‐one percent of the panelists portrayed the texture as hard, 27%
as crunchy, 20% as firm, and 2.4% each as velvety, crisp, rough, gritty, and
tender. Forty-‐one and a half percent of the participants reported the aroma as
nonexistent, 26.8% as flavery, 17.1% as fruity, 7.3% as spicy, 4.9% as sweet, and
2.4% as sour. Ninety percent of the participants described the consistency as
thick, 4.9% as butter, and 2.4% each as thin, and rubbery. Seventy-‐seven percent
of the participants found the mouthfeel to be crunchy, 13.6% as gritty, and 4.5%
each as crisp and smooth.
All 42 panelists participated in the marshmallow descriptive test. Thirty-‐
eight percent of the panelists described the marshmallow’s appearance as puffy,
33% as rounded, 9.5% as symmetrical, 7.1% as creamy, 4.8% each as dull and
dry, and 2.4% as fine. Ninety-‐seven and a half percent of the participants
designated the flavor as sweet, and 2.4% as pasty. Thirty-‐six percent of the
panelists portrayed the texture as springy, 19% as velvety, 12% as chewy, 9.5%
gummy, 7.1% each as gelatinized and moist, 4.8% as crisp, and 2.4% each as
rough and rubbery. Ninety-‐seven and a half percent of the participants reported
the aroma as sweet, and 2.4% as flowery. Seventy-‐eight and a half percent of the
participants described the consistency as gummy, 11.9% as rubbery, 4.8% as
thick, and 12.4% each as butter or thin. Sixty-‐three and a half of the participants
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found the mouthfeel to be smooth, 27.3% as sticky, and 4.5% each as slimy and
gritty.
Discussion
Color Association /Beverage Perception
Panelist beverage perception and opinion is shown more prominently
with each additional analysis and association. Panelists perceived the yellow-‐
colored beverages (light yellow and dark yellow) as being sweeter than the
others. This may be due to an association with lemonade and a sweet correlation
to that beverage based on color similarities. For sourness, results conflicted with
the sweet data, finding the light yellow ranked high along with the dark
chartreuse colored beverage. Participants could have been overwhelmed with
the taste overflow of sample, which could account for the contradictory figures.
A smaller sample of beverages or a longer time in-‐between sampling could
remedy this if the experiment were to be repeated. Similar conduction of a
sensory test was witnessed in the Shankar et al. 2010 study where the subjects
were aware of color conditions with beverage choice. All results show color as a
strong deciding factor in beverage classification.
The emerald beverage was found to be most artificial and most disliked
by the participants. The artificiality could be based on the unusual brightness of
the emerald green color and lack of an association with another beverage. This
could lead to the ranking of most disliked by creating a negative association with
that color disparity in the panelist’s memory.
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The light yellow beverage was found to be most natural and most
preferred by the participants. The recognition of the light yellow color most
likely was due to an association with a similar sport drink color or lemonade
color. This may have lead participants to a ranking of most preferred due to a
feeling of safeness with the color from a basis of memory association.
For temperature, all panelists preferred the beverages cold overall. Some
participants included tepid temperatures fairly high, but the coldest temperature
remained the preference throughout the color variability. Different countries
around the world have patterns and customs that guide drink temperature. In
the United States (where this experiment was conducted), beverage temperature
in this color range, is dominated by a cold preference and is perhaps the major
reason for the data representation here. Future research in this area could
include other colors that are known to vary in temperature, including: black,
brown, or a lighter brown.
Paired Comparison Test
All the panelists identified the correct sample in the paired comparison
test. Possibly the samples were easy to differentiate by that timing of the testing.
In order to account for this, a repeated experiment could change the order of the
testing to check the accuracy of this data. If repeated results were found to show
100% correct identification, verification of these outcomes would be established.
Triangle Test
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All participants were able to identify the different samples in the triangle
test. In order to validate the accuracy of this data, repeated experimentation
could be used where the order of testing was reversed or mixed. This would
allow measures to be seen from multiple testing organizational methods.
Furthermore, not all panelists were able to participate due to dietary
restrictions. In further work, questionnaires should be able to separate out
candidates that cannot participate in the full process.
Scoring Test
The majority of the participants were able to correctly place the samples
of apple juice on the appropriate locations on the scale. The majority of the
panelists scored the pure apple juice as the sweetest and the sourest as the
mixtures of apple juice and a 10% citric acid or 5% citric acid component. The
ability to discern the two highest citric acid contenders was not uniform amongst
the participants, most likely accounting for the small variability in the scoring
found here. This could be due to individual variances found from panelist tasting
ability; as it is a common characteristic to have differing ranges of taste
sensation (Brown 2012). These results could also possibly be due to an
additional issue of taste fatigue, since there were 5 samples consecutively tested.
If repeated, the experiment should lower the sample number to deter this affect.
Ranking Test
All panelists participated in the ranking test, with the majority able to
correctly identify the most and least sour apple juice mixtures. The greatest
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amount of panelists preferred the pure apple juice the most and the mixture of
apple juice and 10% citric acid the least. As previously stated, to prevent taste
fatigue, the panelists could be given fewer samples to compare with more time in
between to deter a overflow effect of the samples.
Duo-‐Trio Test
Almost all of the panelists participated in the duo-‐trio test, and those who
did were able to correctly identify that the Safeway Vanilla Wafers were different
from the standard sample. Incorrect identification of the sample could have been
due to experiencing taste fatigue, recorded incorrect results, or having been
given a defective sample. The panelists believed that the wafers were different
based on varying reasons mainly due to personal preference. Further tests could
thoroughly follow recording procedures, check each sample before given to
panelists, and possibly lower the amount of descriptive terms in order to prevent
these variances.
Descriptive Tests
The majority of the panelists participated in the goldfish cracker
descriptive test. If this study were to be conducted again, the organizer could
question participants before involvement in order to omit those who cannot
participate in all aspects of the experiment. The crackers’ appearance was found
to be golden-‐brown, rough, rounded, asymmetrical, symmetrical, grainy, puffy,
or dull. In order to minimize the difference seen in these results, the organizers
could present a shorter list of descriptive terms, which would assist the panelists
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in honing their sensory evaluation skill. In addition, there are normal variances
in the way the crackers were viewed, possibly from one angle while others view
from a different angle. If this examination was repeated on crackers, a uniform
shaped product could be chosen in place of the fish shape. Test organizers could
also check for regularity of size and shape for uniformity of each cracker.
Consistency, mouthfeel and texture recordings also found similar results of
varying responses, with one exception of the taste with 100% reporting them as
salty.
All of the panelists participated in the raisin and almost all participated in
the almond descriptive tests. The majority found the raisins to by sticky, sweet,
chewy, and fruity. The majority also found the almond to be golden-‐brown,
nutty, hard, brittle, and odorless. In the future, a more fragrant nut could replace
the almond so there is something to report by panelists for odor. As previously
stated, performing some pre-‐selection questions can remedy the lower level of
participation by the subject panelists. This can be conducted by simply omitting
panelists who have a nut allergy or diet condition that keeps them from
participating in all the testing procedures.
As with the other tests, not all panelists participated in the marshmallow
descriptive test. Panelists found them puffy, rounded, symmetrical, creamy, dull,
dry, and or fine. Flavor was found to be sweet, or pasty, and texture as springy,
velvety, chewy, gummy, gelatinized, and or moist, plus others. Varied responses
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could be minimized (as stated previously) by having a shorter recommended
word list.
The results of these tests all show that panelists were able to evaluate
food samples objectively based on given characteristics. Any sensory
examinations that had panelists omitting from participating was due to specific
diet parameters that kept them from consuming those specific foods. In the end,
participants were able to meet all of the goals set forth by the organizers of this
data collection. Students could properly re-‐administer a sensory test on their
own, analyzing color associations and descriptive properties of food samples.
Major changes in a repeat experimental process should include the before
mentioned suggestions including: shorter recommended descriptive word
tables, pre-‐qualifying panelist questionnaires, thorough following of collection
and recording procedures, and possibly an education process to assist panelists
in how to properly test for sensory evaluations. This lab experiment has
introduced the students involved to sensory perception testing and taught all
how to successfully repeat and carry out such tasks in future research.
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NUTR205 Demographic Questionnaire Name______________________________ Group Number _____ Section Number_____ Please answer the following questions. Note: The numbers in parentheses are used for recording data in the spreadsheet only. Your instructor will explain this process in further detail when necessary.
1. Your age, in years: __________
2. Your gender (circle): Male(1) Female(2)
3. Your major (circle/fill-‐in): F/N Other____________________
4. Student Status (circle): Undergraduate (1) Graduate(2)
5. Marital Status (circle): never married(1) married (2) widowed(3)
divorced(4)
6. Living arrangements (circle): alone(1) 1 roommate(2)
2+roommates(3)
7. Do you smoke (circle): Yes(1) No(2)
8. Do you have any food allergies (circle)? If yes please specify Yes(1)
No(2)
________________________________________________________________________
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NUTR 205 Sensory Testing Beverage Questionnaire Name______________________________ Group Number _____ Section Number_____ Do you drink Apple Juice yes No For each of the parameters (sweetness, sourness, naturalness, artificiality, preference and dislike) give the beverage with the most a rating of 5. Give the beverage with the least a ranking of 1. Similarly the one that is almost as sweet as the sweetest beverage receives a ranking of 4, while the next to least sweet receives a ranking of 2. The middle sample will be given a rating of 3.
5 4 3 2 1 For stating what temperature you would the beverage at, state whether you would drink the beverage hot, warm, tepid or cold. Fill in the cell with your choice. Complete the question “Would you drink it?” as either yes or not ONLY! Please do not use words like sometimes or maybe.
Beverage Color and Associations with Other parameters Parameter 1 light
yellow 2 dark yellow
3 chartreuse
4 dark chartreuse
5 emerald green
Sweetness
Sourness
Artificiality
Naturalness
Prefer
Dislike
At what temp would you drink
it?
Would you drink it?
Most Least
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DESCRIPTIVE TERMS To use with Experiment #3, Letter A, Table A-‐1 in Lab Book. When evaluating the foods in this experiment, select one of the words from this list for the appropriate category. Appearance Texture Symmetrical Crisp Asymmetrical Velvety Rounded Rough Dry Hard Golden brown Firm Light brown smooth Thin Rough Viscous Puffy dark Springy Creamy Gritty Dull Gummy Fine Adhesive Grainy Moist Sticky Tender Glossy Chewy Lumpy Flavor Rubbery Crunchy Sweet Gelatinized Bitter Mealy Sour Salty Flat Mouthfeel Rancid Pasty Crisp Sticky Flowery Slimy Fruity Gritty Musky Slick Nutty Crunchy Smooth Aroma Consistency Spicy Flavery Butter Fruity Cheezy Sweet Viscous Sour Thick Thin Rubbery Gummy
30
NUTR205 Sensory Evaluation Name______________________________ Group Number _____ Section Number_____ Duo-‐Trio Test Determine which cookie sample differs from the standard presented first. Standard = 8175 Sample = 6104
Sample = 1108
Which sample differs from the standard? __________ In your opinion what is the major difference? ____________________ Scoring or Rating Test The reference sample, 0110, has been given an arbitrary score of 4. Rate the sour intensity of the other two samples relative to the reference. Sample 420M Sample S723
More sour 1 .________ 2. ________ 3.________ 0110 4.________ 5.________ 6._________ Less sour 7.________
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KEY FOR SENSORY
EXPERIMENT 1 - ASSOCIATION OF COLOR IN BEVERAGES WITH SOURNESS, SWEETNESS, AND PREFERENCE Light Yellow - Mountain Dairy Lemonade Dark Yellow –Xtremo Citrico Vibrante Gatorade Chartreuse – 350 mls. Lemon Lime Gatorade plus 150 mls. Green Squall Powerade Dark Chartreuse – Green Squall Powerade Emerald Green– Watermelon Gatorade EXPERIMENT B - PAIRED COMPARISON TEST 635T1 = 0% 573T2 = 1% EXPERIMENT C - TRIANGLE TEST 777Cl = 0% 542E2 = 0% 112H9 =1% EXPERIMENT D - RANKING 495P2 = 0% 543K8 = 1% 695F8 = 2.5% 192L3 = 5% 555D7 =10% EXPERIMENT 2 - DUO-TRIO 8175 (Standard) = Nabisco Nilla Wafers 6104 = Safeway Vanilla Wafers 1108 = Nabisco Nilla Wafers EXPERIMENT 3 - SCORING 420M = 1% 0110 = 2.5% S723 = 5%
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References Brown AC. 2010. Food evaluation. In: Food preparation – NUTR 205: Custom edition for San Diego State, 4th ed. United States: Cengage Learning. P23-‐8. Ioannides, Y. , Seers, J. , Defernez, M. , Raithatha, C. , Howarth, M. , et al. (2009). Electromyography of the masticatory muscles can detect variation in the mechanical and sensory properties of apples. Food Quality and Preference, 20(3), 203-‐215. Marzec, A. , Kowalska, H. , & Zadrozna, M. (2010). Analysis of instrumental and sensory texture attributes of microwave-‐convective dried apples. Journal of Texture Studies, 41(4), 417-‐439. McClure, S. , & Lawless, H. (2010). Comparison of the triangle and a self-‐defined two alternative forced choice test. Food Quality and Preference, 21(5), 547-‐552. Ross, C. , Weller, K. , Blue, R. , & Reganold, J. (2009). Difference testing of merlot produced from biodynamically and organically grown wine grapes. Journal of Wine Research, 20(2), 85-‐94. Sandra, S. , Stanford, M. , McDaniel, M. , & Goddik, L. (2004). Method development for assessing the complete process of crumbling cheese using hand evaluation. Journal of Food Science, 69(4), SNQ127. Shankar, M. , Simons, C. , Shiv, B. , McClure, S. , Levitan, C. , et al. (2010). An expectations-‐based approach to explaining the cross-‐modal influence of color on orthonasal olfactory identification: The influence of the degree of discrepancy. Attention, Perception & Psychophysics, 72(7), 1981-‐1993. Stillman, J. (1993). Color influences flavor identification in fruit-‐flavored beverages. Journal of Food Science, 58(4), 810-‐812. Young ND, Sanders TH, Drake MA, Osborne J, Civille GV. 2005. Descriptive analysis and US consumer acceptability of peanuts from different origins. Food Qual Prefer 16:37-‐43.
