Sensory Evaluation Lab Report
Tala L. Moshref Nutrition 205 Lab Section 4 Fall 2013 San Diego State University
Abstract Sensory evaluation is a scientific method designed to construct accurate evaluations based on human senses. Various methods of effective tests were used to determine likes or dislikes, preferences and differentiation between products. These sensory evaluation tests were performed in a food preparation laboratory setting at San Diego State University. The carefully designed tests included color association and perception of beverages, difference test, evaluation of food products using descriptive terms, paired comparison test, triangle test, duo-trio test, scoring or rating test and ranking test. A total of 89 untrained students, 10 males and 79 females, participated in this experiment. The general results from these test suggested that color of a food product has a major role in food acceptance. The results also concluded that determining a food products texture, aroma, flavour, appearance, mouth feel and consistency is variable due to gender, food sensitivity, health status and other factors.
Introduction Sensory evaluation of foods, food preferences and consumer acceptability are considered important criteria in food production. There are a range of methods used to evaluate foods which are categorized as either sensory (subjective) and objective tests. Sensory (subjective) evaluation is a discipline that uses scientific measurements to evaluate food products with consideration of personal preference and involvement of five senses (touch, smell, taste, sight and hearing). The food industry uses the sensory factors to research, develop new products and evaluate merchandise quality and suitability. The sensory evaluation itself has been divided into two categories: effective and affective tests. Effective tests are usually organized using trained panellists. The method of the effective tests is to identify differences through discriminative or descriptive tests. In other words, are the samples different from one another and what their differences are? On the other hand, affective tests are usually conducted by an untrained group of panellists and the methods are based on personal preferences of liking and disliking a product. Each of these methods are used to determine a specific area being tested (Understanding Food Principles & Preparation by Amy Brown, 2008). This scientific method of food evaluation was emerged in 1940 by expert tasters evolved with tea, coffee and cheese production. Over the years this practice has evolved and is used for product development focusing on preferences and likes and dislikes. Also, competitor analysis, quality optimization and price reduction, formulation and ingredients are other important basis covered by this scientific method. In addition, sensory evaluation helps providing objective scientific evaluation on a food product. (Sara E. Kemp, 2008)
Color Association and perception of food products, is a difference test used by industry to measure the relationship between color, flavour and odor of products and consumer’s perception. In this test a few samples of a product are presented and the panellists are to grade them with a specific characteristic such as flavour intensity (Brown 2008). Studies have shown that the way a product is presented changes the way it is perceived by the consumer. For example, a soap product was examined for the packaging, size, color and odor in an experiment conducted by Elia Gatti, Monica Bordegoni and Charles Spence in (2013). Products contributing to a better appearance significantly influenced on consumer acceptability. A product’s size, color and odor effect on consumer’s perception and brand preference. A number of senses contribute to an overall experience of a product and are known as cross modal correspondences. All together, consumers are usually more attracted to the products that satisfy a few sensory perceptions compared to the products that only satisfy a small percentage of the senses. In addition, a person’s food acceptance is highly effected by their cognitive influences and expectations. According to a research study done by Maya U. Shankar and others (2010), color of a product provides a perception of flavour and identity but what people expect from their food product greatly effects their decision. Vision usually provides a perception before tasting the food product and it is directly related to perception. Evaluation of food products using explanatory terms is a method of Descriptive Testing. Using this method, researchers are able to gather detailed information about appearance, flavour, texture, aroma, consistency and mouth feel of a food product. In evaluation of food products a list of explanatory terms is provided to the panellists. Appearance of a food product can be determined by size, color and surface condition. For example, symmetrical, asymmetrical, dark, glossy, rounded, dry and smooth can be vocabulary provided for evaluating appearance. Flavour
is a combination of taste, aroma and mouth feel. Descriptive terms such as sweet, sour, bitter, nutty, fruity and floury can be used to determine flavour. Texture is defined as the way the tactile senses respond to physical qualities of a food product. Terms such as rough, gritty, mealy, hard, velvety and tender are examples of terms used to describe texture. Aroma greatly influences like or dislike of a food when volatile molecules reach the olfactory sensation. For aroma, terms such as burnt, sweet, sour, spicy and flowery can be provided to the panellists. Consistency of the food product can be described with the term thin, chewy, gummy and brittle. Lastly, mouth feel of a food product can be evaluated with a variety of terms including slimy, crunchy, smooth, crisp, sticky and slick (Amy Brown,Understanding Food Principles & Preparation Lab Manual, 2011). In addition to the options provided, there are multiple factors contributing to a panellist’s perception of a food product. In a research done by Jianshe Chen and Jason R. Stokes in (2012), the eating process including, biting, mastication, amount of saliva and the size of particles before swallowing influence the sensory perception. There are many factors that can effect a panellist’s perception on a food product. In addition, tasting a few food products at a given time may influence the evaluation of the food product. Meaning, the later tests may be compromised by inaccurate results. In addition, this research studies the differences between taste and flavor with texture and how they are influenced by different factors. The food industry uses many different methods to create new goods or improve and older product. These tests are usually given to a trained group of panellists to accurately evaluate the areas being studied. Paired comparison, test is a method of difference test involving two samples. The goal of this test is to identify the sample that is more intense in the quality being tested such as sweetness, sourness, thickness or thinness. In Duo-Trio test, standard sample is provided in addition to two other samples. The goal of this experiment is selection of the food
product that is most similar to the standard sample. In Triangle test which is another difference method, panellists are provided with three samples two of them being the same and are asked to identify the odd sample. In scoring or rating test the panellists are given a standard sample with a determined degree of a certain quality. Then, the panellists are provided with other samples and are to rate them in accordance to the standard sample. Ranking test is another method used by the food industry to determine suitability for consumer satisfaction. In this test more than two samples are provided and the goal is to rank the food products according to their intensity of a specific quality such as color, odor and flavour. Besides factors such as aroma, flavour and mouth feel there are other aspects of food preference. For example, physiological responses that influence the panellist’s experience and evaluation have been studied by Ivan E. De Araujo, and others (2012). In this research, the effects of nutrients on physiological pathways and food intake have been researched. Also, this study focuses on how flavour of a food product influences the stimulation of the brain and the amount of hormones (particularly dopamine) secreted. In addition, in this research post-ingestive signals and their effect on food experience have been studied. Food evaluation is a multidimensional subject. Researchers study different aspects of food suitability and consumer acceptability. Another approach to food preference is to study the consumer’s social, economical and family status. The effects of age, gender, marital status and social status on food behaviour have been studied by Eva Roos and others (1998). This research showed that food consumption behaviour is more elevated amongst men and women who are married and amongst those who have a higher income. Socioeconomic status was the main factor contributing to men’s response to food behaviour. There were more factors such as marital status and household responsibilities affecting a woman’s response to food acceptability.
The purpose of the study done by the Nutrition major students as SDSU was to learn and practice the proper way of performing a sensory evaluation. As a part of this experience the students were to evaluate the effects of the five senses in judgment of food products and beverages. Another goal of this study was to teach the students how to evaluate food products by texture, aroma, consistency, appearance and flavour. Identifying differences in samples, ranking multiple beverages in order of their intensity and preference, and evaluating differences of given samples with a standard sample were other goals of this study.
Methods Panelists The panelists for the sensory evaluation were all the students registered in course NUTR 205 in fall of 2013 at San Diego State University. The lab for this class was divided into four sections. Three of the subdivisions met on Monday and Wednesday morning, early afternoon and late afternoon. The fourth group met on Friday mornings. Each subgroup consisted of 21-24 students from different ethnicities and the total number of participants was 89. The age of the participants ranged from 19 to 35 years old and about 79% were between the ages of 19-23. Out of the 89 panelists, about 89% were female and the other 11% were male. The majority (93%) of the participants were single, leaving a small percentage for married and divorced attendees. In addition, 73% of the participants in this experiment were undergraduates, while the remaining 27% were graduate students. Additionally, 12% of the students lived alone, 27% lived with one roommate and 61% lived with two roommates. Lastly, 99% of the panelists were non-smokers and about 10% had food allergies (shellfish, gluten, dairy, eggs, salmon, soy, cinnamon, vanilla, preservatives and mayonnaise). Refer to appendix A.
Environment The location of this experiment was at the West Commence Building on the second floor room WC 204. This space was designed similar to a kitchen with a total of 6 sinks including dish washing, hand washing and food prepping sinks around the sides of the room. There were a total of 6 conventional ovens, 1 freezer, 1 refrigerator and 7cabinets for storing cooking equipment. In the front middle of the room, there was a long counter top was designed for the instructor. There were 2 doors for entrance and exit on the sides of the instructor’s counter. There were 27 seats organized in 5 rows for the student’s right across from the instructor’s table. The seats were surrounded by six cooking stations all around the room. In the back of the class, behind the seats, there was a large white board with some charts and numbers on it. There were no windows and as a result no natural light in this libratory. Multiple florescent lights were used to illuminate the room.
Color Association/Perception of beverages For this evaluation, 5 beakers containing different liquids were set up at the instructor’s station. Each beaker contained a different liquid with a different color. The colors were organized from light to dark and from left to right. Beaker 1 was labeled as light yellow, beaker 2 as dark yellow, beaker 3 as chartreuse, beaker 4 as dark chartreuse and beaker 5 as emerald green. The panelists were to evaluate the liquids for sweetness, sourness, naturalness, artificiality, preference and dislike by just observing the beakers. They were asked to rank the liquids from 1-5, 1 being the lowest and 5 being the highest in each category. Another procedure for the panelists was to state if there were any of the drinks they would consider drinking and the
answers were limited to yes or no only. If their answer was positive, then the panelists were asked to state in which temperature they’d consider drinking the liquid. The options for temperature were cold, tepid, warm and hot. As the last part of this experiment, the panellists were asked if they drink Apple Juice or not. Refer to appendix B.
Difference Tests A general protocol for all the difference tests was provided to the panelists. For accuracy, they were required to perform all the experiments individually and not in groups. The panelists were asked not to share their experience and feelings about the food products with one another. In addition, they were required to perform the experiment in silence and not show any facial expressions during the tests. Finally, each panelist was given a cup of room temperature water to drink in between each try.
Evaluation of Food Products Using Descriptive Terms For this experiment, each panelist was presented with 4 small paper cups containing bite size food samples. The samples were gold fish, raisins, almonds and marshmallows. The food products were to be evaluated for appearance, aroma, flavour, texture, consistency and mouth feel. The participants were provided with a list of descriptive terms for each food product. It was essential for the panelists to choose one word from each category that best described the product. The number of descriptive words varied for each category and food product. For
example, to evaluate the appearance of gold fish, there were 14 descriptive words and to evaluate the consistency of raisin, there were 7 words available to choose from. View appendix C.
Paired Comparison Test For this difference test, there were 2 coded beakers (635T1 and 573T2 ) containing apple juice at the instructor’s station. Five students from the front row were selected to pour two samples of apple juice in small paper cups. The sample cups were coded respective to the original beakers. The cups were then distributed amongst the panellists each person receiving two coded beverages. The procedure was to try both samples and compare the intensity of sourness and choose the sourest drink.
Triangle Test: For this experiment, there were three beakers containing apple juice at the instructor’s counter. Each beaker was labeled with a different code (777C1, 542E2 and 112H9). Five students from the front row were selected to pour the samples in small paper cups. The cups were labeled respective to the original beaker. Each panelist received three sample cups simultaneously and had to point out the odd sample.
Duo-Trio Test
The panellists were to sample three differently coded vanilla cookies for the Duo-Trio test. The standard vanilla cookies were coded as 8175, and the other two samples were coded as 6104 and 1108. The panellists were asked to determine which of the cookie samples differed from the standard sample presented in the beginning of the experiment. In addition, the panellists were to share what was the major difference in the sample they picked as different compared to the other two. View appendix D.
Scoring or Rating Test For this test, the students were presented with a coded reference sample of apple juice. This sample was given an arbitrary rating of 4 for sourness on a scale of 1-7 (for 1 being more sour and 7 being less sour). The panellists were to try two other coded samples and determine where they belonged on the scale of 1-7 compared to the reference sample. View appendix D.
Ranking Test: There were five beakers containing different samples of apple juice at the instructor’s station. Each beaker was coded; beaker 1 as 695F8, beaker 2 as 495P2, beaker 3 as 192L3, beaker 4 as 543K8 and beaker 5 as 555D7. Five students were selected to pour the samples in small paper cups coded respective to the original beaker. Each person was given 5 differently coded sample cups. The panellists were asked to try the samples and classify them in descending order of intensity with 1 being the most intense in flavour and 5 being the least intense. In
addition, the participants were asked to rank the samples by personal preference 1 representing their most and 5 representing their least favourite.
Results Beverage Color Association The results of the Beverage Color Association and perception of beverages was as follows. Emerald was perceived to be the sweetest with (43.82%) votes, light yellow (25.84%), dark yellow (19.10%), dark chartreuse (6.74%) and lastly chartreuse was perceived as the least sweet beverage (4.49%). In addition, light yellow was perceived as the most sour beverage with (44.94%), dark yellow (17.98%), chartreuse (14.61%), dark chartreuse (12.36%) and finally, emerald green was chosen to be the least sour with (10.11%). Refer to figure A-1 to view the results on a bar graph.
Panelist Color Association Determineing Sweetness & Sourness of Beverages
Percentages
43.82 60 44.94 40 25.84 19.1 17.98 14.616.74 12.36 10.11 4.49 20 0
Sweet Sour
Sweetness/Sourness Figure A-1
The results for the most natural and most artificial beverages were calculated. Emerald had a result of (79.78%) perceived to be the most artificial, dark yellow (8.99%), dark chartreuse
(5.22%), chartreuse (4.49%) and yellow with (1.12%) was chosen to be the least artificial. In addition, the light yellow beverage was determined to be the most natural with (96.62%) votes, dark yellow (2.25%), chartreuse (1.12%) and no votes were put in for cark chartreuse and emerald. View figure A-2 for reference.
Panelist Color Association Determineing Naturality and Artificiality of Beverages
Percentage
120 96.63 100 80 60 40 8.98 1.12 4.49 1.12 2.25 20 0
79.77 Natural
5.62 0
0
Artificial
Natural/Artificial Figure A-2
The results for preferring and disliking the most are as follows. Light yellow was most preferred with (86.54%), chartreuse (13.48%), dark chartreuse (7.86%), emerald (5.62%) and dark yellow with 4.49% was chosen to be the least preferred. On the other hand, emerald with (59.55%) was chosen to be the least preferred, dark yellow (26.97%), dark chartreuse (5.62%), light yellow (4.49%), and finally chartreuse with (3.37%) was chosen to be disliked the least. See figure A-3 for a summary of results.
Panelist Color Association Determining Prefrence & Dislike of Beverages
Percentage
59.55 80 68.54 60 26.97 40 5.62 5.62 4.49 4.49 13.48 3.37 7.86 20 0
Prefer Dislike
Prefer/Dislike Figure A-3
The results for the willingness to drink the beverage are as follows. The votes for light yellow were (96.62%), for dark yellow (5.56%), chartreuse (62.92%), dark chartreuse (39.99%) and emerald with (74%) was the least desired beverage to drink. Also, the percentage of people who said no to drinking the beverage is as follows: Emerald (74.16%), dark chartreuse (60.67%), dark yellow (49.44%), chartreuse (37.08%) and yellow (4.49%). View figure A-4 for a summary of results.
Panelist Color Association & Willingness to Drink Beverage
Percentage
120 96.62 100 60.67 74.16 80 49.4462.92 39.33 37.08 60 25.84 40 4.49 5.56 20 0
Yes No
Yes/No
Figure A-4
The results for the temperatures the panellists were willing to drink the beverage are as follows. The cold temperature results were, dark chartreuse (95.51%), light yellow, dark yellow and emerald (94.38%) and chartreuse (.94%). For hot temperature the results were: emerald (3.37%), light yellow (2.25%), chartreuse and dark chartreuse (1.12%) and dark yellow (0%). The results for warm temperature were: (2.25%) for dark yellow and chartreuse, (1.12%) for dark chartreuse, and (0%) for yellow and emerald. The experiment results for tepid were: (5.62%) for emerald, (4.49%) for light yellow and dark yellow and (3.37%) for chartreuse and dark chartreuse. Figures A-5 through A-8 are provided for reference.
Panelist Color Association & Willingness to Drink Beverage Cold
Emerald Green; 25% Light Yellow; 25% Dark Dark Chartreuse; 25%Yellow; 25% Chartreuse; 0%
Figure A-5
Panelist Color Association & Willingness to Drink Beverage Hot
Light Yellow; 29% Emerald Green; 43% Chartreuse; 14% Dark Chartreuse; 14%
Figure A-6
Panelist Color Association & Willingness to Drink Beverage Warm
Dark Chartreuse; 20% Dark Yellow; 40% Chartreuse; 40%
Figure A-7
Panelist Color Association & Willingness to Drink Beverage Tepid
Light Yellow; 21% Emerald Green; 26% Dark Yellow; 21% Dark Chartreuse; 16% Chartreuse; 16%
Figure A-8
The results for drinking apple juice were recorded and are as follows. (50.56%) said yes and (23.59%) said no. Refer to chart A-9.
Percent Panelists Drinking Apple Juice
No; 32% Yes; 68%
Figure A-9
Evaluation of Food Products Using Descriptive Terms The results for the appearance, aroma, flavour, texture, consistency and mouth feel of raisins, gold fish, almonds and marshmallows are shown in tables C-1 through C-4. Table C.1 Top Four Percentages of Sensory Evaluation for Raisin
Appearance
Aroma
Flavor
Texture
Sunken
24%
Fruity
43%
Sweet
52%
Chewy
Glossy
18%
Sweet
39%
Fruity
35%
Gummy
Dark
17%
Flowery
8%
Flowery 7%
Rubbery 13%
Rubbery 22%
Dry
11%
Nothing
8%
Bitter
Moist
Viscous
Gritty
5%
Consistency
Mouth feel
42%
Chewy
48%
Sticky
24%
Gummy
25%
Slimy
11%
Smooth
11%
9%
5%
62%
8%
Table C.2 Top Four Percentages of Sensory Evaluation for Goldfish
Appearance
Aroma
Gldn Brown 38%
None Burnt 29% Spicy 9%
54%
Sweet
3%
Dry Rough Grainy 7%
27% 7%
Flavor
Texture
Salty
78%
Stale
Consistency
Mouth feel
Crunch
51%
Brittle
48%
Crisp
45%
7%
Crisp
37%
Cheesy
24%
Crunchy
37%
Sharp
6%
3%
Thin
13%
Gritty
11%
Flat
3%
Flaky Gritty 3%
Chewy
6%
Smooth
2%
Table C.3 Top Four Percentages of Sensory Evaluation for Almonds
Appearance
Aroma
Gldn Brown 27%
None
91%
Dry
Burnt
6%
Flat
Light Brown 26%
Flowery
2%
Rough
Sour
1%
Salty Bitter 2%
27%
11%
Flavor Nutty 81%
Texture Hard 12% 3%
26%
Consistency
Mouth feel
Thick
56%
Crunchy
62%
35%
Gritty
21%
Crunchy
25%
Chewy
Firm
22%
Thin
3%
Crisp
8%
Rough
11%
Rubbery
3%
Smooth
4%
Table C.4 Top Four Percentages of Sensory Evaluation for Marshmallows
Appearance
Aroma
Flavor
Texture
Consistency
Mouth feel
Puffy 83%
Sweet 87%
Sweet 68.5%
Gummy 22%
Gummy 33%
Smooth 22%
Rounded 7%
Nothing 7%
Floury 15%
Springy 22%
Chewy 27%
Sticky 29%
Dull 2%
Flowery 3%
Pasty 12%
Velvety 17%
Thin 12%
Slimy 19%
Gelatinized 12%
Butter 9%
Gritty 2%
Smooth 2%
Paired Comparison Test The results for the Paired Comparison Test are as follows. 635T1 with (1.12%) was determined to be less sour apple juice and sample 573T2 with 98.88% was determined to be the sourer of the two samples. Refer to figure A-10 to view results.
Paired Comparision Test Determining the Sourer Sample of Apple Juice 120 100 80 Percentage 60 40 20 0
98.88 Sample 635T1 Sample 573T2
1 Sourness Figure A-10
Triangle Test
The results for this test are as follows: Sample 112H9 with (97.75%) was determined to be the odd sample. Citric acid was added to this beverage. There were no votes for sample 777C1 and (2.25%) for sample 542E2.
Triangle Test Determining the Odd Smaple of Apple Juice 120 100
97.75 Sample 112H9
80 Percentage
Sample 777C1
60
Sample 542 E2
40 20 0 Oddness
Figure A-11
Duo-Trio Test Sample 6104, Safeway brand cookie with (96%) votes was determined to be different from standard vanilla cookie, which was Nabisco brand. Sample 1108 was also manufactured by Nabisco (4%) was chosen to be similar to the standard sample. In addition, the odd sample 6104, was chosen to differ from the standard sample by less vanilla flavour with 57%, crunchiness with 27%, and dryness with 15%. My conclusion is that the main difference between the odd sample and the standard was the flavour. The results are shown in figures A-12 and A-13.
Duo-Trio Test Choosing Odd Sample Compaired to Standard Vanilla Cookie 150 100 Percentage
96
Sample 6104 Sample 1108
50 0
4 1 Difference Figure A-12
Duo-Trio Test Determining Differences of Odd Sample with Standard Vanilla Cookie 0.8 0.6 0.4 0.2 Percentage 0
0.57 0.15
0.27
Differences of Odd Sample
Figure A-13
Scoring or Rating Test The reference sample, 0110, contained 2.5% Citric Acid. Sample 420M contained 1% Citric Acid and sample S723 contained 5% Citric Acid. The reference sample was evaluated as a number 4 on a scale of 1 to 7, 1 being more sour and 7 being less sour. The results are as follows. Sample S723 was at a scale of 2 considered more sour and sample 420M was at a scale of 6 considered less sour. See figure A-14.
Rating Test Determining the Intensity of Sourness Compaired to Refrence Sample 8 6 Sourness 4 2 0
Sample 0110 Sample 420M Sample S723 samples of Apple Juice Figure A-14
Ranking Test: Sample number 5, coded as 555D7 with 10% citric acid added to it was determined to be the most sour beverage (96.6%). Sample number 3, coded as 192 L3 with 5% citric acid added was determined to be the second sourest sample (88.76%). Sample number 1, coded as 695F8 with 2.5% citric acid added was determined to be the third sourest drink (87.69%). Sample number 4 coded as 543K8 with 1% citric acid added was determined to be the fourth sourest sample (86.52%). Lastly, sample number 2 coded as 495P2 with 0% citric acid added was determined to be the least sour sample (86.52%). In addition, sample number 2 coded as 495P2 (57.3%) was most preferred beverage amongst the panellists. Sample number 4 coded as 543K8 (62.92%) was the second chosen beverage. Sample number 1coded as 695F8 (75.28%) was third selected beverage. Sample number 3 coded as 192L3 (78.65%) was fourth preferred beverage. Lastly, sample number 5 coded as 555D7 (94.38%) was the least desired sample. For a summary of results concerned the sourness and preference of the samples, view figures A-15 and A-16.
Ranking Test Determining Degrees of Sourness of Apple Juice Samples 88.76 86.52 86.52
Different Samples
87.64 96.6 80 82 84 86 88 90 92 94 96 98 Sourness Figure A-15
Ranking Test Determining Levels of Prefrence of Apple Juice Sample 78.65 57.3 62.92 75.28 94.38
Different Samples
0
20
40
60
80
100
Least Preferred Figure A-16
Discussion: In the color association and perception of beverages test, the emerald green drink (watermelon Gatorade) was determined to be the sweetest. As mentioned in the article written by Elia Gatti and others (2013), the color and appearance of a beverage has an important role in determining the taste of it. The color of watermelon Gatorade is very similar to Nyquil/Vicks which is a medication used for colds. Nyquil has a very syrupy appearance as well as a strong sweet taste. Panellists may have viewed the emerald green as the sweetest drink because of its
association with Nyquil. In addition, emerald green beverage was perceived to be the most artificial product. This result as well could be because of association with Nyquil. Since this pharmaceutical product is a mixture of unnatural compounds, it leaves an impression of unnaturalness. Interestingly, the emerald green drink was disliked the most and was one of the least preferred drinks amongst the five samples. This could be because of the panellists past experiences and association of the color with having a cold. In addition, emerald green drink was chosen to be the least preferred drink which could be again, because of association of unnaturalness, and poor health. The light yellow beverage was perceived to be the sourest drink amongst all five. The color of this drink was similar to a common drink, lemonade. The main ingredient of lemonade is lemon which is acidic and tart. The panellists may have associated this color to freshly made beverage with lemons. For the same reason perhaps this beverage was identified as the most natural amongst all five drinks. In addition, when the panellists were asked to determine which beverage they liked better, the light yellow was preferred the most. Accordingly, when the panellists were asked which beverage they would drink, the light yellow was the first choice. This could be a result of a pleasant association such as a hot summer day, a picnic or dinning out. The panellists were also asked what temperature would they drink their preferred beverage. There were more votes for cold rather than hot, warm and tepid. Dark chartreuse was voted the highest and light yellow, dark yellow and emerald green followed shortly after. For the hot, warm and tepid temperatures there were a lower percentage of votes. The reason could be because of associating brightly colored drinks such as juices and energy drinks with being cold. In addition, the season and time of the day could have an effect on this choice.
Evaluating food products using terms to describe flavour, texture, aroma, mouth feel and appearance for raisins, gold fish, almonds and marshmallows was conducted. As mentioned in the article written by Jianshe Chen and Jason R. Stokes in (2012), the amount of time a food is being chewed, the amount of saliva and the size of the particles can influence the sensory perception. Also trying a few food products in a short period of time will decrees the quality of tasting. Evaluating the four food products was done early before the panellists had tried so many other samples. After tasting raisins, the highest votes determined that the appearance was sunken, the aroma was fruity, the flavour was sweet, the texture was chewy and the mouth feel was sticky. For the goldfish, the highest percentages conducted that the appearance was golden brown, there was no aroma, the flavour was salty, the texture was crunchy, the consistency was brittle and the mouth feel was crisp. For the almonds the highest voted determined that the appearance was golden brown and dry, there was no aroma, the flavour was nutty, the texture was crunchy, the consistency was thick and the mouth feel was crunchy. Evaluation of marshmallows defined the following results: the appearance was puffy, the aroma and flavour were sweet, the texture was gummy and springy, the consistency was gummy and the mouth feel was sticky. The results for this experiment could have been affected by many factors. For example, the panellists were not told to try the samples in order. Even though water was provided to clean and refresh their pallet, most certainly small particles of the food samples remained in their mouth and effected the evaluation of the next item. Other factors such as degree of familiarity with the food products, the environment, time limitation, temperature, time of the day could also reflect the results. Also, like or dislike of the food product, sensitivity, health status (for example, if recovering from a cold) could all affect the results for this test. In addition, the panellists were not told about the experiment, so they could have been at different
levels of hunger and satiety or may have been chewing gum or even smoking before the experiment. The variation of results for the difference tests including paired comparison test, triangle test, scoring test and ranking test was because of the percentage of citric acid added to the beverages. In paired comparison test, the sample with 0% citric acid was determined to be less sour. In the triangle test, the sample with 1% citric acid added was pointed out as the odd sample. In the scoring or rating test, the sample with 5% citric acid added was determined to be 2 degrees sourer than the standard sample and the sample with 1% citric acid was determined to be 2 degrees less sour than the standard. For the ranking test also, the beverages were graded on the degrees of sourness. The apple juice sample containing 10% citric acid was determined to be the least favourite and the sample with 0% citric acid added was the most favourite amongst the panellists. Many factors could contribute to the results for these tests. Physiological responses to the acidity levels of the food, as mentioned in the research done by Ivan E. De Araujo, and others (2012) could greatly affect the decision of the panellists. Also, familiarity with an apple juice with a certain amount of acidity and unexpected tartness of other drink could have left a negative influence on the panellists. Also, the difference tests were done after trying the food samples of goldfish, raisins, almonds and marshmallows. Referring to the article written by Jianshe Chen and Jason R. Stokes in (2012), this could greatly affect the panellists tasting sensitivity and as a result inaccurate determination.
In all of these tests, the cups were not
labeled as they were given to the panellists. Some errors might have happened when the selected students were distributing the samples. Also, since the panellists were told that they are going to try apple juice, the ones who disliked apple juice were turned off by that and that could affect how they evaluated it. In duo-trio test, sample 1108 was Nabisco Nilla Wafers and was
identified to be similar to the standard sample. The sample that was determined to be different was First Street brand. In this test, the results could have been influenced by brand familiarity, food acceptability and the time of the test (it was the last test performed). In addition, the color and texture and mouthfeel of the cookies could greatly affect the panellist’s decisions. During the distribution of the cookies, most panellists were excited to try the cookies and loudly expressed how much they liked that type of cookie. The anticipation and excitement of eating tasty cookies could greatly change the results of this test. Even though most areas of this sensory evaluation test were designed and planned neatly, the panellists were not aware of their participation in it. This could highly affect the results of this experiment. Some people may have had a meal prior to the class and some other might have been hungry. Health status, cultural diversity and food familiarity could also influence the results. In addition, the study was done in different segments; the NUTR 205 lab has four section and they are all at different times of the day. This could seriously influence the results. Some of the steps can be improved for future tests. The students can be verbally notified in a previous class to come prepared to participate in an experiment. They can be told to eat something 2 hours before class, not smoke or chew gum prior to the test to get more accurate results. The test can also be planned at a day/time that all students can participate. For example, perhaps dedicating 2 lecture sessions to not only have all the students together, but also have them participate in the evaluations with fresh and clean pallets.
References Amy Brown, Janelle M. Walte, Karen Beathard. 2011. Understanding Food Principles & Preparation: Lab Manual. Fourth Edition. California. Wadsworth. Amy Brown. 2011.Understanding Food Principles & Preparation. Fourth Edition. California. Wadsworth. Elia Gatti, Monica Bordegoni, Charles Spence. 2013. Investigating the influence of colour, weight, and fragrance intensity on the perception of liquid bath soap: An experimental study. Food Quality and Prefrence. 31:56-64. Eva Roose, , Eero Lahelma, Mikko Virtanen, Ritva Prattala, Pirjo Pietinen. 1998. Gender, socioeconomic status and family status as determinants of food behaviour. Social Science & Medicine. 46(12)1519-1529. Ivan E. De Araujo, Jozelia G. Ferreira, Luis A. Tellez, Xueying Ren, Catherine W. Yeckel. 2012. The gut–brain dopamine axis: A regulatory system for caloric intake. 106(3):394-399. Jinashe Chen, Jason R. Stokes. 2012. Rheology and tribology: Two distinctive regimes of food texture sensation. Trends in Food Science & Technology. 25:4-12. Maya U. Shankar, Carmel A. Levitan, Charles Spence. 2010. Grape expectations: The role of cognitive influences in color–flavor interactions. Concsiousness and Cognition. 19(1):380-390.
Pankaj B Pathare, Umezuruike Linus Opara, Fahad Al-Julanda Al-Said. 2013. Colour Measurement and Analysis in Fresh and Processed Foods: A Review. Food and Bioprocess Technology 6(1):36-60. Sarah E Kemp. 2008. Application of Sensory Evaluation in Food Research. 43(9):1507-1511.
