121example04 - Sensory Evaluation of / Perceived Tastes...

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Unformatted text preview: Sensory Evaluation of / Perceived Tastes Nutrition 121 1362 Dr. Heather Graham INTRODUCTION As one is well aware, our food choice are not always determined by our nutritional needs, they are also determined by our cultural and family traditions, psychological variables and our / own individual sensory characteristics of how our brains perceive the five taste which are; sweet, salty, sour, bitter and umami. The salty taste is our ability to detect Sodium Chloride (NaCl), sweet taste is as associated with carbohydrates with foods that include sugar and fruits. The sou‘r/ taste detects acids in foods such as those found in citrus fruits and the final taste is Umami which is the taste response to glutamic acid salts in things like monosodium glutamate (MSG). The fallowing four experiments are sensory evaluations used to detect the thresholds at which we detect these five tastes. Such experiments are very helpful for food scientists when conducting research on new food products. The test panel for these experiments was made up of 28 people of various ethnic backgrounds, mostly non-smokers, consisting of 19 females and 9 males with and average age of about 23 years, as shown in Table I found in the Results section of this report. The objective of experiment 1 was used for the determination of the approximate threshold concentrations of salty, sour, sweet and bitter solutions as well as the detection of MSG. / The goal of experiment 2 was to examine the effect of temperature on the perceived sweetness of a sucrose solution. The goal of experiment 3 was to illustrate how genetics determine the ability to taste certain chemicals such as Phenylthiocarbamide (PTC), and Sodium Benzoate. The goal of experiment 3 was to illustrate the adaptation of taste receptors and how quickly one would get used to a particular taste if one was exposed to it with frequency. For this test Sodium Chloride was used. METHODS W In this experiment 5 stations were set up for each perceived taste. Each taste station had three solutions, labeled in Moles, from lowest to highest concentration. The study group was then assigned to discover at which point of concentration they could detect a particular taste. The only exception was the solution for MSG which was either a YES they could detect or NO they could not detect. For the Sucrose solution (Sweet): 0.01M (Sample 1), 0.02M (Sample 2), 0.04M (Sample 3) For the Sodium Chloride solution (Salty): 0.01M (Sample 1), 0.02M (sample 2), 0.04M (Sample 3) For the Tartanic Acid solution (Sour): 0.0002M (Sample 1), 0.0005M (sample 2), 0.001M (Sample 3) For the Quinine solution (Bitter): 0.0005M (Sample 1), 0.001M (Sample 2), 0.002M (Sample 3) For the MSG solution: 0.02M (Sample 1) Each participant tasted each of the 5 types of solutions, starting with the lowest (/ concentration to determine if a taste was detected, then the results were recorded at the lowest concentration at which the taste was detected. The results are shown in Table 2a and Table 2b in the Results of this report and the findings are noted in the Conclusions section. V, In this experiment the study group was assigned to discover the effect of temperature on taste. 3 samples were given with a 10% sucrose solution in each. Sample 1 was on ice at 4°C, Sample 2 was at the room temperature of 25°C, and Sample 3 was warm at 49°C. The group was then asked to rank the three temperatures for sweetness, I being the least sweet and 3 being the most sweet. The results were then recorded and are shown in Table 3 in the Results section of this report and the findings are noted in the Conclusions section. / In this experiment the study group was assigned to determine the ability to taste certain chemicals. For this experiment the chemicals Phenylthiocarbamide (PTC) and Sodium Benzoate was used. Each individual was asked to first taste the plain paper as the control to recognize the taste of the paper, then asked to taste the other papers to see if they could taste the chemicals. The group then recorded their results by indicating either a Yes they could taste or No they could not. The results are shown in Table 4 in the Results section of this report and the findings are noted in the Conclusions section. / In this experiment the study group was asked to illustrate the adaptation of taste receptors by placing a small amount of a 3% Sodium Chloride solution in their mouth and hold it there while recording the time with a timer. When the sensation of the saltiness had subsided they were asked to stop the clock and record the time in seconds. The results are shown in Table 5 in the Results section of this report and the findings are noted in the Conclusions section. RESULTS TABLE 1: Group Data / ........... .................. 67.5%, 39.5%. Cafi‘cEEiEii Ada}; """""" Emma”; dither“w 23 Female Male Non-smoker 575% 175% 145% 35% 75% Calculations: Age: Total of all ages + 28 participants Percentages: # of each participant + 28 participants = % (Average round up to 100%) Ethnic Group: Determined by major ethnic background (2 or more of similar ethnic background listed). Other = Half one race, half another TABLE 2a: Threshold Concentration of Primary Tastes / .............................................. __________ EB?“ ........ “SEE; .............................. “SEE; __________ «gt; ........... Lowest (:onccntmfifln . . H ..................... “-1 ......... .......... - 4 ,s .............. V ; ........ _ _ g i Highest Concentration 44% 14.5% 74.5% 18.5% I T 82% 3.5% 7 Other 1' 1 Could not taste Could not taste Calculations: ‘‘‘‘‘‘‘‘‘‘ " Percentages: # of each participant -I- 27 participants = % (Average round up to 100%) / TABLE 2b: Umami Test for MSG N0 3.25%“ Calculations: Percentages: # of each participant -I- 27 participants = % (Average round up to 100%) TABLE 3: Effect of Temperature on Taste / 23.33 % __ Mostsweez‘ "2—233 0%, ' ""36'.'6'"6""% Fhioderate'ii- Sweet 23.33 % L 57.66 % 23.33 % Lean sweet; 34.33 % 11.66 % 53.33 0/0 _ __ ToiaI-i 100 % 100 % Calculations: Percentages: # of each participant + 26 participants = % (Average round up to 100%) TABLE 4: Perception Test of PTC and Sodium Benzoate /’ ................................................................................... M. . _____________________ 13ft; ......................................................................................................... 18;"; I) Egj '[ Tastes (Yes) pi____._-..__.§9.33/; .,__ iiiii H non-Tastes (No) 1 10.5% I 14.5% Total 100% l 100% ....................................... Percentages: # of each participant + 28 participants = % (Average round up to 100%) TABLE 5: Adaptation of Taste Receptors to 3% NaCl Solution ""KJE-Eg—fiiEe—"EE—SEEEHEQ W / _ ....... ..'. ......... ................ .. _.. . .. . .. Calculations: Total of all times in seconds + 28 participants = Average time in seconds ._ CON CLUEION S In the experiment for testing for threshold concentrations of primary tastes the results were varied, with ethnic background, age and smokers v.s. non-smokers not seaming to make much of a difference, however the sample size of these groups was very low. Surprisingly, 82% of the test group could not taste the sour concentration of tartaric acid at all, and 74.5%V/ could taste the salty solution of sodium chloride at theJcfi’w/est concentration. The bitter solution was fairly even with a difference of only 4% with 48% tasting it at the lowest concentration. Almost the entire sample group of 96.5% was able to detect the MSG solution. A couple of limitations existed; some of the group reported that the samples were in the wrong order and this could mean that the threshold detection could be inaccurate. Also some of the participants wrote there findings on the wrong number and forgot to rinse between tasting solutions, which could also cause the threshold detection to be inaccurate. With these findings the group has therefore concluded that this particular experiment would need to be repeated with more control and also a larger sample group of different ethnic backgrounds, smokers and older V, participants in order to come to any solid findings. / In the experiment for testing the effect of temperature on taste 57.66% of the test group felt that the solutions were only moderately sweet at the room temperature of 25°C. 42.33% of the group felt that the sweetest solution as the ice temperature of 40C and the least sweet being the warm solution at 49°C with 53.33% of the group. This would stand to reason V’/ that things like ice-cream and sodas would seem more sweet when served ice cold, but combinations of less sweet with warm items pare well together; such as hot fudge with cold vanilla ice—cream. A limitation did exist on the experiment though with one of the previous groups not leaving the tubes of solutions out for the next group to rotate. This meant that next group did not know which test tube was in the water bath and fridge the longest, this meant that the next group was unable to determine if the samples were at the accurate temperature and the detection could be inaccurate. With these findings the group has therefore concluded that this particular experiment would need to be repeated with more control in order to come to any solid findings. f In the experiment for testing the perception of m/C and Sodium Benzoate almost :33 entire test group was able to taste the chemicals. 89.5% were able to taste the PTC and 85.5% were able to taste the Sodium Benzoate. Ethnic background, smoking and age did not seem to / have an effect. V A limitation did exist on the experiment though; several of the group members were together when tasting the strips and many of the members made comments on the taste before the others could try them. It is theorized that the sample group may have been influenced by the other members and had perceptions before ever trying the strips, with this theory the group has therefore concluded that this particular experiment should be repeated with each member of the group by themselves without the influence of the other group members when tasting the strips to see if the findings are the same. Also, a larger sample size with a more varied ethnic background, age and smoking differences is needed to come to any solid conclusions. In the experiment for the adaptation of tastes receptors to a 3% NaCl solution the average time was 32.07 second: This result, in combination with the test for salty tastes in experiment 1, would indicate that most people are sensitive to the taste of salt, however that taste diminishes (or we get used to it) with the more salt we are exposed to put in our diets. A limitation did exist on the experiment though; in the directions the study group was asked to stop the time at which the “sensation of the saltiness had subsided”. The word “subsided” was unclear as each individual may interpret it differently. Did “subside” mean when you could no longer taste the NaCl solution? or just when the taste wasn’t that strong anymore? With this finding the group has therefore concluded that this particular experiment would need to be repeated with a more clear definition as to what is required of the participants in order to come to any solid findings. Personal Note: The data would support that for these experiments 33.33% of the males in this group, ages 19 to 21, do not know how to follow directions : ) ...
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This note was uploaded on 01/16/2012 for the course NUTR 121 taught by Professor Heathergraham during the Fall '11 term at Truckee Meadows Community College.

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121example04 - Sensory Evaluation of / Perceived Tastes...

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