Sensory Evaluation Manuscript

Kyrié Baca

Nutrition 205L

April 16, 2012

Abstract

The sensory experience of foods is critical in consumer enjoyment of food products and beverages and is fundamental for commercial success. Human selection of foods is determined by many factors using the innate senses of sight, smell, taste, touch, and sound. The purpose of this study was to evaluate food products and beverages using color association tests, descriptive tests and difference tests in order to demonstrate the influence of the sensory experience on food choice. The study took place in the food science laboratory at San Diego State University. Students in both Nutrition 205 laboratory sections participated as panelists in this study. A color association test was performed on five samples of beverages in the colors of light yellow, dark yellow, chartreuse, dark chartreuse, and emerald. A descriptive test was performed to analyze the appearance, aroma, flavor, texture, and consistency of 4 foods (goldfish, raisins, almonds, and marshmallows). Difference tests performed included the paired comparison, duo-trio, triangle, ranking and rating test methods. Sensory tests were performed simultaneously among panelists and the laboratory assistant for the course performed data collection. Color association test results were highly variable and indicative of the variation of the sensory experience among individuals, as this test is dependent on the integration of all five senses. Results indicated a broad range of sensory perceptions in descriptive tests among panelists for goldfish, raisins, almonds, and marshmallows. Additionally, an overwhelming precision in the perception of foods was observed by the use of difference tests.

Introduction

Sensory Evaluation

Human selection of foods depends on many factors determined by innate senses. The senses of sight, smell, taste, touch, and sound effect the way that a food product or beverage is perceived. Exposure to various stimuli in food products and further perception of those stimuli form the criteria for our selection of foods. The eyes receive the first impression of foods by evaluating a food’s shape, color, consistency, serving size, and overall appearance. Aroma is the quality of a flavor that is strongly influential in the acceptance or rejection of a food product (Brown, 2011). Volatile molecules, those capable of evaporating in the air, are perceived by the olfactory system and send signals of odor perception to the brain. Perhaps the most influential factor in food choice is taste. Taste occurs when molecules of a food product are detected by the gustatory cells in the oral cavity and the taste stimuli is then sent to the brain via nerve cell transmission. Texture, firmness, thickness, and astringency of foods are perceived by the sense of touch. This tactile sense is also stimulated by chemethesis, the perception of the heat and coolness of foods that are not physically hot or cold. Finally, water content detection, freshness, and doneness of food products is achieved through the sense of sound (Brown, 2008).

Evaluations of food quality are based on sensory characteristics of foods and our personal experience of foods, as they are perceived by the five senses. Analytic and affective tests make up the basis for sensory evaluation techniques. Analytic tests detect differences between foods and are typically conducted by trained personnel and include discriminative tests and descriptive tests. Discriminative tests detect discernible differences between food products. Triangle, duo-trio, paired comparison, ranking, ordinal, and threshold dilution tests evaluate differences between food samples in sensory evaluation. Descriptive tests quantify differences between products based on flavor and texture profiles by detailing the specific flavors and textures of a food or beverage. Additionally, they are used to detail the specific flavors and textures in a food. Affective tests, on the other hand, are administered to untrained consumers to detect preferences using Hedonic scales, ranking, paired preference tests, and facial tests (Brown, 2011).

The sensory experiences evoked by foods and beverages are fundamental in our enjoyment of those products, and equally important for commercial success. Research techniques are therefore, critical in measuring, understanding, and optimizing consumer experience of food products to meet consumer sensory needs. Because the human sensory experience is so specific and detailed, sensory evaluations should not be considered as a routine process, but rather as a tailored process to certain products, situations, or assessment scenarios. It is important to understand consumer perception and behavior and to use that knowledge with a multidisciplinary approach to consider the broad scientific background of sensory evaluation including: physico-chemistry, psycho-physics, psychology, physiology, neuroscience, and genomics (Editorial, 2008).

Food choice is not only limited to the human senses, but also transcends our emotions. Food affects the way that we feel and has been identified as a key element in determining food choices. Mood has also been identified as a behavioral outcome of food alongside cognitive and physical performance. This parameter in sensory evaluation is important because it is easy to measure in the laboratory setting and may be strongly interactive with the senses (King, 2010).

Paired Comparison Test

The paired comparison test is a difference test that involves the presentation of two samples to the panelist simultaneously. The taster is then asked to select the sample that has more of a particular characteristic (sweetness, sourness, thickness, thinness, etc) (Brown, 2008).

Triangle Test

The triangle test is a sensory evaluation design that is also used frequently to evaluate sensitivity. This is a difference test performed on three coded samples of food products. In this test to differentiate between products, three samples are presented simultaneously with two of the samples the same and the other different. Panelists are then asked to identify the sample that is not the same among the three (Brown, 2008).

Ranking Test

A ranking test is a type of difference test in which two samples are presented simultaneously and the panelist is asked to rank the samples by intensity of a specific characteristic (aroma, flavor, color, etc.). The rank of 1 designates the sample with the greatest intensity of that particular characteristic (Brown, 2008).

Rating Test

A rating test is a type of difference test used to determine the relative intensity of a food. Rating tests analyze food products or beverages by comparison to other samples based on the intensity of a particular characteritistic (sweetness, sourness, etc).

Duo – Trio Test

The duo-trio test is a sensory evaluation design that is commonly used to evaluate sensitivity. This sensory evaluation technique involves simultaneous exposure to three taste stimuli in the form of a food product or beverage with the first test sample as a reference, and the last two stimuli from two alternative samples (Brown, 2008). This specific format likely helps panelists to identify and examine the dimensions of difference and reduces the memory load associated with the task. Therefore, with more stable memory function, the duo-trio test is a reliable measure of specificity (Kim, 2010).

Texture

Texture is the sensory manifestation of the surface properties of a food along with structural and mechanical properties. Texture is detected through several of the senses including sight, sound, and touch. Texture is a set of sensory properties analyzed through many sensory channels. The perception of texture in the oral cavity is largely dependent upon the way that food breaks down in the mouth and the transformation of that food in the mouth. Consumer perception of food products, therefore, is largely effected by the experience of texture (Lenfant & Lorent, 2009). The study of texture is extremely dynamic because of the highly complex process of mastication that provides a stimulus for perception of a food product. Our evaluation of a food’s texture is influenced by the structure of a particular food as well as the resistance to mechanical forces to break it down.

Color

The way in which we experience the flavor of foods and beverages results from the integration of all the senses when the food or beverage is perceived (Shankar, 2009). Chronologically, appearance is the first factor considered by the consumer when making a decision about a food product (Bayarri, 2001), although a combination of cognitive and environmental factors can influence the way sensory information is interpreted. Color is largely important in our experience of food and drink and has a role as an indicator of edibility, especially in regards to flavor and intensity (Shankar, 2009). Visual color cues of beverages have been shown to stimulate the perception of identity and intensity of flavor, our satiety, and other appetitive responses (Spence, 2010). Color is a main attribute of food products and beverages. Product color not only conditions the consumer to accept a food, but it also stimulates previous information on the safety of the food or other food attributes, whether the consumer’s previous experiences were positive or negative (Bayarri, 2001). Therefore, the way that we view intensity of food and beverages may reflect learned associations of simultaneous color-flavor occurrences making it a largely important factor in sensory evaluations of consumer perception (Shankar, 2009).

Sourness

Sour taste is a simple taste based largely on the concentration of hydrogen ions in a food product or beverage. Previous studies have given varying conclusions regarding the sour tastes of different acids. Other studies have demonstrated that acids act differently in their degree of sour taste. Acids in foods give off chemical feeling factors in addition to a sour taste. They can also cause astringency with inorganic acids seeming to have more astringent qualities than organic acids. In their studies on pickle and sauerkraut products, Johanningsmeier et. al. proposed the hypothesis that sour taste intensity is linearly correlated with the summation of the molar concentration of organic acid species that contain protonated carboxyl group(s) and free hydrogen ions. Therefore, our perception of sour taste is a complicated chemical mechanism that may involve more than just free hydrogen ions in a product (Johanningsmeier, 2005).

Methods

Panelists

Panelists for this study included 43 students from San Diego State University Nutritional Food Sciences laboratories with a total of 5 males and 38 female panelists. The demographic data was taken from the prior demographic questionnaire that was given in a previous lab study. One student had a birthday from the time that the demographic questionnaire had been given last; thus, only age data was altered appropriately while the other data remained unchanged. Twenty-one students participated in the first laboratory section and 22 students participated in the second laboratory section. All students were administered a demographic questionnaire that was evaluated prior to sensory evaluations.

Students ranged from 18 to 43 years of age with a mean age of . All students were nutrition majors in the College of Exercise and Nutritional Sciences at San Diego State University, 86% of the participants were undergraduate students while 14% were pursuing a graduate degree. Eighty-eight percent of students had never been married, 9% were married at the time of the testing, and 2% had been divorced. Living arrangements were also variable as 5% of the panelists lived alone at the time of the tests, 12% had one roommate, and 67% had two or more roommates. The majority of panelists were nonsmokers (98%), with only 2% being smokers. Eighty-eight percent of panelists did not report food allergies while 12% noted one or more food allergies to corn, soy, nuts, dairy, shellfish, peanuts, yeast, malt, barley, and/or eggs (Appendix A).

Environment

All sensory evaluations were performed in the food science laboratory that was temperature-controlled and had normal lighting. The room had tile flooring, six tables and sinks placed around the perimeter of the room and a large desk spanning the front of the room from which samples were distributed. The room also contained a refrigerator and freezer, no windows, and two doors that remained closed during the sensory evaluations.

Administrators distributed 4-oz. cups of distilled water without minerals to every student for proper palette rinsing before and in between each sensory trial so as not to interfere with tasting. Bite-sized samples of selected food products and approximately 1.5 oz. samples of beverages were placed into 2-oz. white, paper cups by the administrators. Administrators designated all sample codes for sensory tests. The panelist seated at the front of each row was responsible for collecting samples from the administrators and distributing them appropriately to the panelists seated in their row. This procedure remained constant for every sensory test in which samples were consumed. Data collection was performed in an open fashion, as administrators essentially polled the entire sample of panelists (indicated by the raising of a hand). Data was then recorded by an administrator using Microsoft Excel. The same procedure of data collection was repeated for every sensory evaluation.

Color Association

Panelists were given a sensory testing beverage questionnaire in which beverage color was evaluated using associations with other parameters. A sample of five juice samples of equal volumes were prepared in 100 mL beakers and displayed at the front of the testing room on a counter. Administrators of the sensory test stood behind the samples at the front of the room and defined the respective parameters for each step of the sensory test. For each parameter, such as sweetness, sourness, naturalness, artificiality, preference and dislike, students were asked to give the beverage with the most of one particular characteristic a rating of 5. The beverage with the least of that characteristic was given a 1. Similarly, the beverage with the “almost as” characteristic received a ranking of 4, while the “next to least” of that characteristic received a ranking of 2. The middle sample of the same characteristic was given a rating of 3. To state the temperature in which the beverage would be preferably consumed, the panelist was to state whether they would drink the beverage hot, warm, tepid, or cold. Lastly, panelists were asked to complete the question “would you drink it?” as either yes or no only. Panelists recorded individual ratings in a chart (Appendix B). Panelist color preference data was obtained by a raise of hands.

Descriptive Tests

Evaluation of food products using descriptive terms

Panelists began sensory evaluations at the same time, which was initiated by the administrators. Food products were evaluated based on appearance, aroma, flavor, texture, and consistency by using the descriptive terms provided in the table in Appendix C. This table was distributed to each panelist for reference during this descriptive test. Every characteristic of the food product was described using one word. Each participant then recorded test results in Table A-1 of the Nutrition 205 Laboratory Notebook (Appendix D). One administrator obtained data by polling, indicated by the raising of a hand for every food and respective description. It is important to note that, in addition to one student that did not participate in this test, there was one student that did not test the almonds due to a nut allergy, and one student did not test the raisins for dietary reasons.

Difference Tests

Paired Comparison Test

Panelists marked the respective sample codes on a sheet of paper and placed samples on top of the respective number. The apple juice with 0.5% citric acid sample code was 635-T1, and the apple juice with 1.0% citric acid sample code was 573-T2. Each panelist tasted both samples provided and was asked to determine which sample had the greater intensity of sourness. Panelist responses for intensity were indicated by using the words “greater” and “lesser.” Each participant recorded respective data in Table B-1 (Appendix E) of the Nutrition 205 Laboratory Manual. Panelist paired-comparison test data was obtained by a raise of hands.

Triangle Test

Panelists received two identical apple juice samples with assigned sample codes of 777-C1, 542-E2, and 112-H9. Samples 777-C1 and 542-E2 were both regular apple juice samples, whereas the sample 112-H9 was apple juice infused with citric acid. Panelists were asked to identify the odd sample of the series. Data and observations were recorded on Table C-1 (Appendix F) in the Nutrition 205 Laboratory Manual. The total number of correct responses in the class were determined and results as to the likelihood of selecting the odd sample by chance were determined collectively by a raise of hands.

Ranking

Panelists were given five samples of apple juice and were asked to rank the series of samples in order of sourness intensity and preference. Sample code 495-P2 contained no citric acid, 543-K8 contained 1% citric acid, 695-F8 contained 2.5% citric acid, 192-L3 contained 5% citric acid, and 555-D7 contained 10% citric acid. Each panelist consumed each of the coded samples one by one, with appropriate palette rinsing between each sample. Ranking was performed by giving the most intense sample a rank of 1, the least intense sample a rank of 5, and all other samples on a gradient of sourness between 2 and 4; two being almost the most sour, and 4 being almost the least sour, three in the middle. Each panelist recorded their own selections in Table D-1 of the Nutrition 205 Laboratory Manual (Appendix G). Panelist ranking test data was collected by a raise of hands.

Rating

Panelists were given three samples of apple juice of varying acetic acid concentrations. The sample juice (#0110) was given an arbitrary score of 4 on a scale of 1, being more sour, to 7, being less sour. The first test sample code was 420 M and was apple juice with 1% citric acid, and the second test sample code was S723 and contained 5% citric acid. Panelists were asked to consume the reference sample first, cleanse the palette using distilled water, then taste the first test sample to determine its relative sourness compared to the reference sample. Perceptions of sourness were indicated by marking the sample number on the score from 1 to 7 according to that sample’s relative sourness (to the reference sample, score 4). After rinsing the palette a second time, the second test sample was then evaluated using the same procedure and plotted on the same scale by relative sourness. Panelists marked results on the Sensory Evaluation Sheet (Appendix H). Panelist rating test data was collected by a raise of hands.

Duo-Trio

Panelists were given three samples of wafer cookies in this evaluation. The Standard (#8175) was a Nabisco “Nilla” Wafer, one sample (#6104) was a Safeway Vanilla Wafer, and the other sample (#1108) was the same as the standard. Panelists were asked to determine which cookie sample differed form the standard that was presented first, and to state what the major difference was between the different sample and the standard.

Panelists were also asked to describe in one word what they thought the determining quality of the duo-trio test was by using a list of descriptors for general characteristics. Panelists recorded individual results on the Sensory Evaluation sheet (Appendix I). Panelist duo-trio test data was obtained by a raise of hands.

Statistical Analysis

Data collection and calculations were performed by a lab assistant and entered into Microsoft Excel. Percentages were calculated by dividing the number of responses for a test parameter by the total number of students that participated in that particular test. Graphs of percentile scores for each test parameter were also generated using Microsoft Excel.

Results

Color Association

On average, most panelists agreed that the light yellow beverage was most natural (93%; Figure 4) looking and they preferred it most (71%; Figure 5). There were also minimal differences in the most disliked beverage as most panelists chose the emerald colored beverage (64%; Figure 6). However, opinions of the sweetest, sourest, and most artificial beverage were more different and distributed more evenly about the different colors (Figures 1-3). The light yellow (58.1%) and chartreuse (80%) beverages were more likely to be drunk, while dark yellow, chartreuse, and dark chartreuse colored beverages had less than a 50% response to the questions “Would you drink this?” (Figure 7). Additionally, most panelists visualized themselves drinking all of the beverage samples cold (Table 1).

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

Table 1.

Temperature

Light Yellow

Dark Yellow

Chartreuse

Dark Chartreuse

Emerald

Cold

95.3%

95.3%

95.3%

95.3%

95.3%

Hot

0%

2.3%

0%

0%

2.3%

Warm

0%

0%

2.3%

2.3%

0%

Tepid

11.6%

7%

0%

0%

0%

Descriptive Tests

Evaluation of Food Products Using Descriptive Terms

The results for descriptive tests were less conclusive than the color association tests. Results were very mixed among description choices for appearance, flavor, texture, aroma, and consistency (Tables 2-6). Tables below demonstrate the four most chosen descriptors for each food in the respective category for sensory perception.

Table 2.

Goldfish

Raisin

Almond

Marshmallow

Appearance + percentage of student choice

Golden-Brown

(31%)

Dry

(36%)

Golden-Brown

(32%)

Puffy

(38%)

Dry

(26%)

Rough

(29%)

Dry

(17%)

Rounded

(33%)

Rough

(9.5%)

Dark

(9.5%)

Light-Brown

(15%)

Symmetrical

(9.5%)

Rounded (9.5%)

Asymmetrical

(9.5%)

Rough

(9.8%)

Creamy

(7.1%)

Table 3.

Goldfish

Raisin

Almond

Marshmallow

Flavor + percentage of student choice

Salty

(100%)

Sweet

(52.4%)

Nutty

(87.8%)

Sweet

(97.6%)

Fruity

(33.3%)

Flat

(9.8%)

Pasty

(2.4%)

Bitter

(9.5%)

Sweet

(2.4%)

Pasty

(2.4%)

Table 4.

Goldfish

Raisin

Almond

Marshmallow

Texture + percentage of student choice

Crisp

(43%)

Chewy

(40%)

Hard

(41%)

Springy

(36%)

Hard

(2.4%)

Gummy

(24%)

Crunchy

(27%)

Velvety

(19%)

Gritty

(2.4%)

Gritty

(14%)

Firm

(20%)

Chewy

(12%)

Mealy

(2.4%)

Lumpy

(9.5%)

Crisp

(2.4%)

Gummy

(9.5%)

Table 5.

Goldfish

Raisin

Almond

Marshmallow

Aroma + percentage of student choice

Flavery

(78.6%)

Fruity

(73.8%)

None

(41.5%)

Sweet

(97.6%)

Spicy

(9.5%)

Sweet

(21.4%)

Flavery

(26.8%)

Flowery

(2.4%)

None

(7.1%)

Flavery

(2.4%)

Fruity

(17.1%)

Sweet (4.8%)

Sour

(2.4%)

Spicy

(7.3%)

Table 6.

Goldfish

Raisin

Almond

Marshmallow

Consistency + percentage of student choice

Cheesy

(66.7%)

Gummy

(64.3%)

Thick

(90.2%)

Gummy

(78.6%)

Thin

(23.8%)

Rubbery

(16.7%)

Butter

(4.9%)

Rubbery

(11.9%)

Thick

(7.1%)

Thin

(11.9%)

Rubbery

(2.4%)

Thick

(4.8%)

Viscous (2.4%)

Thick

(7.1%)

Thin

(2.4%)

Butter

(2.4%)

Difference Tests

Paired Comparison Test

All 43 students judged the apple juice sample with 1.0% citric acid to have a greater intensity of sourness than the apple juice sample with 0.5% citric acid.

Triangle Test

A large majority of panelists (95.3%) identified the apple juice with citric acid sample to be different than the other samples. A small percentage of panelists (2.3%) selected sample 777-C1 as the odd sample of the three, and the same percentage selected sample 542-E2 as the odd sample. Results of the triangle test may be seen in Figure 8.

Figure 8.

Ranking

Sample 555-D7 was deemed most sour of the samples (90.7%), and sample 495-P2 was most preferred among panelists (60.5%). However, sample 192-L3 was also somewhat preferred (20.9%). Results may be observed in Tables 7 and 8.

Table 7. Sourness

Code

1

2

3

4

5

459-P2

0%

0%

0%

4.7%

95.3%

543-K8

0%

2.3%

4.7%

90.7%

4.7%

695-F8

0%

0%

95.3%

4.7%

0%

192-L3

9.3%

88.4%

0%

0%

0%

555-D7

90.7%

9.3%

0%

0%

0%

Table 8. Preference

Code

1

2

3

4

5

459-P2

60.5%

20.9%

14.0%

2.3%

2.3%

543-K8

7%

62.8%

0%

18.6%

11.6%

695-F8

9.3%

14.0%

74.4%

0%

2.3%

192-L3

20.9%

0.0%

7.0%

67.4%

4.7%

555-D7

2.3%

2.3%

4.7%

11.6%

79.1%

Rating

The majority of the panelists perceived sample 420M to be less sour than the reference sample of apple juice, but perceptions on intensity of the greater sourness fell along a gradient from scores 4 (same amount of sour taste as reference sample) to 7. All panelists perceived sample S723 to be more sour than the reference sample, indicated by the 58.1% designation of score 1 and the 41.9% designation of score 2. Results from the rating test may be observed in Table 9.

Table 9.

Code

1

2

3

4

5

6

7

420M

0%

2.3%

0%

2.3%

11.6%

62.8%

20.9%

S723

58.1%

41.9%

0%

0%

0%

0%

0%

Duo-Trio

Nearly all panelists selected the Safeway Vanilla Wafer as the cookie not the same as the reference cookie, meaning that those panelists also selected Nabisco “Nilla” Wafer as the same wafer as their reference cookie (98%). Only 2% of panelists believed that the Safeway Vanilla Wafer tasted most similar to the reference sample.

When asked what the distinguishing characteristic was between the samples, most students selected “stale” (26%), but many others thought the sample was different than the same based on the test sample being “crunchier” (12%) or “harder” (14%). Results from the duo-trio test may be observed in Figures 9 and 10.

Figure 9.

Figure 10.

Discussion

The research presented in this study was designed to demonstrate the effect of many variables on sensory evaluation of foods.

Color Association

In previous research, Shankar et. al. demonstrated that consumer’s perception of “chocolat-eyness” of chocolate samples was influenced by the external color shell of the product (Shankar & Levitan, 2009). The results of this study confirmed previous knowledge that both color and label information can elicit different ratings for the flavor of foods. In our study, color did seem to have a strong affect on perception of beverage samples. Perceptions of the natural quality, preference, and dislike of a beverage were associated with color, while perceptions of sweetness, sourness, and artificiality had a weaker association with color. This may suggest that our decision-making process on whether or not we choose to drink a beverage and like it may rely on our perception of color and perhaps previous experiences with tastes associated with particular colors. Our perception of the natural quality of beverages may work in a similar way. On the other hand, perhaps the scale of the degree of sweetness, sourness, and artificiality of beverages register on a continuum in our minds rather than a decision of yes or no (Shankar & Levitan, 2009).

Descriptive Tests

Results of the descriptive tests were similar to previous research. It is quite typical for results to be varied depending on the number of descriptive words available to use to explain appearance, flavor, texture, aroma, and consistency. Texture perception is of strong influence in the experience of taste and is perhaps one of the most important parameters examined in this study. A study by Lenfant et. al. provided implications that the perception of crispiness and stickiness of foods is altered along the course of mastication of those foods. Therefore, the differences in descriptives seen in the current study may perhaps be explained by the variability in the mastication process among individuals when assessing textures of food products (Lenfant & Lorent, 2009).

Descriptive Tests

Sour Taste: Paired Comparison, Triangle, Ranking and Rating tests

Johanningsmeier et. al. examined the chemical basis for sour taste and their findings led them to the prediction that sour taste intensity is linearly correlated with the molecular concentrations of organic amino acids in a product. This was reflected in the current study in the paired-comparison, triangle, ranking and rating tests results. Panelist perceptions of sour taste were relatively conclusive with the amount of citric acid in a given sample. The majority of panelists shared the same perceptions of sour taste when they consumed different levels of apple juice with citric acid (ex. 1%, 2.5%, 5%, etc). This model provides a simplistic model to explain and predict sour taste, which can prove extremely useful in the food and beverage industries (Johanningsmeier, 2005).

Duo-Trio Test

One study by Kim et. al. revealed that the number and the order of presentation of samples, particularly in a duo-trio test and a triangle test can have a bearing on ones perception of a product. Samples were presented simultaneously in the current study, which may have affected the results. In a professional sensory lab setting it may be more feasible to present each panelist with the reference sample for these types of tests first, followed by additional samples for either comparison or determination of the odd sample (Kim, 2010).

Limitations

Some limitations of our study included the environment and panelist sample. The environment was dissimilar to a proper sensory evaluation environment in that the details in the room were very busy and perhaps distracting. Additionally, test administrators were talking through the entire evaluation experience, which could have distracted panelists from experiencing their perception of the food or beverage clearly. Appropriate instruction on how to give the assessment should be given to the test administrators and carried out in a precise way to avoid testing error (Editorial, 2008). The method for receiving samples included a responsibility of the first person in each row of chairs to collect the samples and distribute them equally along the row. This style of sample distribution relies on one individual’s memory and offers a platform for mistakes to be made. This task should ideally be carried out by trained test administrators of sensory evaluations.

Panelists were also chosen from a nutrition class at San Diego State University. This could potentially affect the results of the study as the sample was not truly random but rather was composed of a large number of individuals with a strong knowledge base of health and nutrition. It is important when evaluating the sensory evaluation of food and beverage products, to obtain a large and random sample and to have a distraction-free environment in order to avoid these types of errors.

Future Implications

Future studies should consider these potential errors and incorporate these suggestions into the study design. It would also be interesting to follow up with the color association tests used in this experiment. Future research may consider assessing the same parameters (sourness, sweetness, natural quality, preference, etc) and follow the evaluation with tests in which panelists actually consume the beverages in order to see how their experience of the products compare with their prior perception based on color.

Works Cited

(2008) Editorial: Application of sensory evaluation in food research. International Journal of Food Science and Technology, 43, 1507-1511.

Bayarri, S., & Calvo, C. (2001). Influence of color on perception of sweetness and fruit flavor of fruit drinks. Food Science and Technology International, 7(5), 399-404. Retrieved from http://fst.sagepub.com/

Brown A. 2008. Understanding Food Principals and Preparation. 3rd Edition. California: Wadsworth. p. 654.

Brown A, Walter J, Beathard K. Understanding Food Principles and Preparation, 4th edition: Lab Manual. Belmont, CA: Wadsworth/Cengage, 2011.

Johanningsmeier, S. D. (2005). A hypothesis for the chemical basis for perception of sour taste. Journal of Food Science, 70(2), 44-49.

Kim, M. (2010). Comparison of d0 estimates produced by three versions of a duo-trio test for discriminating tomato juices with varying salt concentrations: The effects of the number and position of the reference stimulus. Food Quality and Preference, 21, 504-511.

King, S. C., & Meiselman, H. L. (2010). Development of a method to measure consumer emotions associated with foods. Food Quality and Preference, 2010, 168-177.

Lenfant, F., Loret, C., & , (2009). Perception of oral food breakdown. The concept of sensory trajectory. Appetite, 52, 659-667.

Shankar, M. U., & Levitan, C. A. (2009). The influence of color and label information on flavor perception. Chemosensory Perception, 2, 53-58.

Spence, C. (2010). The influence of auditory cues on the perception of, and responses to, food and drink. Journal of Sensory Studies, 25, 406-430.

Zampini, M., & Wantling, E. (2008). Multisensory flavor perception: Assessing the influence of fruit acids and color cues on the perception of fruit-flavored beverages. Food Quality and Preference, 19, 335-343. Retrieved from www.sciencedirect.com

Most Disliked Beverage

Light YellowDark YellowChartreuseDark ChartreuseEmerald0.070.1860.0230.070.605

Would You Drink This?

YesLight YellowDark YellowChartreuseDark ChartreuseEmerald0.8140.4650.5810.3720.256NoLight YellowDark YellowChartreuseDark ChartreuseEmerald0.140.4880.3720.5810.698

Beverage Color

Percentage of Response

Triangle Test

Apple Juice + Citric AcidApple JuiceApple Juice0.9534883720930230.02325581395348840.0232558139534884

Beverage Sample

Percentage of Students Who Identified Odd Sample

Duo-Trio Test: Identifying Odd Sample

ReferenceSafeway Vanilla Wafer (6104)Nabisco "Nilla" Wafer (1108)0.00.9761904761904760.0238095238095238

Duo - Trio Test : Descriptor Used to Designate Odd Sample

drynesscrunchinessless vanillarancidstalehardertexturecolorflakytastehollowunsweetSweet0.00.1190476190476190.07142857142857140.00.2619047619047620.1428571428571430.09523809523809520.07142857142857140.02380952380952380.1428571428571430.02380952380952380.00.0476190476190476

Sweetest Beverage

Light YellowDark YellowChartreuseDark ChartreuseEmerald0.3720.3020.0230.070.186

Sourest Beverage

Light YellowDark YellowChartreuseDark ChartreuseEmerald0.2790.1630.140.2560.116

Most Artificial Beverage

Light YellowDark YellowChartreuseDark ChartreuseEmerald0.0230.1160.0230.00.047

Most Natural Beverage

Light YellowDark YellowChartreuseDark ChartreuseEmerald0.8840.00.0230.00.047

Most Preferred Beverage

Light YellowDark YellowChartreuseDark ChartreuseEmerald0.6740.070.1160.0470.047