Lab Report: Sensory Evaluation

Lab Report: Sensory Evaluation


Food is essential in maintaining a healthy life. However, acceptance of food is not always determined by its nutritive value, but by the preference of each person. Nevertheless, food preference is complex and often influenced by several factors. Among these elements are traditions, psychological factors, and foodways including friends/family as well as sensory attributes (color, tastes odor and texture) (“Lab #4: Sensory Evaluation of Food”). Both taste and odor are constituents of flavor, and they have a significant influence on food intake and acceptability.

Genetics, on the other hand, has an immense impact on lives. It is equally a critical factor, which affects food acceptability. In that regard, nutrigenomics shows substantial effects on sensory evaluation. Simply defined, nutrigenomics refers to how common dietary chemicals influence health by altering gene expression (“Lab #4: Sensory Evaluation of Food”). By extension, taste is a genetic trait. Thus, nutrigenomics contributes to taste perception, particularly, among people from diverse background.

Body organs can determine and make choices on particular food qualities. The brain, for instance, can detect both taste and odor. Generally, five different tastes can be recognized by the brain. These are called primary components of taste (“Lab #4: Sensory Evaluation of Food”). They include umami, salt, sour, sweet, and bitter. A sweet taste is associated with sugars in food substances while salty one is mostly caused by the presence of sodium chloride. Umami tastes, on the other hand, are perceived as a result of the existence of glutamic acid salt in some food materials (“Lab #4: Sensory Evaluation of Food”). Finally, a sour taste is the result of organic acids present in a food substance. Ultimately, sensory evaluation has become critical in conducting research related to food, food-quality-control, and food product marketing.

The purpose of Lab #4 was to utilize sensory evaluation techniques to illustrates principles of taste used in the sensory analysis. The experiments that were administered included the ranking test where participants were required to rank solutions based on the concentrations they perceived during the trial. Additionally, scoring tests were indicated by expressions such as most sweet, moderate sweet and low sweet. During the study, the four experiments that were conducted include determining threshold concentration of the primary tastes, the adaptation of receptors, effects of temperature on tastes, and perception of PTC and sodium benzoate (“Lab #4: Sensory Evaluation of Food”).


The sensory evaluation was performed using panelists from diverse culture, sex, and other social life forms. Thus, the respondents in the study included Whites, Blacks, Hispanics, and Asians. Both gender and age balance were observed.

Experiment 1: Threshold Concentration of the Primary Tastes.

The goal of this first experiment was to allow the participants to evaluate and determine approximate concentrations of salty, sweet, sour, and bitter.


  1. Sucrose (0.01M, 0.02M, 0.04M)
  2. Sodium chloride0.01M, 0.02M, 0.04M),
  • Tartaric acid (0.0005M, 0.001M,0.002M),
  1. Quinine,
  2. MSG (0.02M),
  3. Pipets
  • Distilled water.

Procedure: The participants were allowed to taste each of the solutions labeled as 1, 2, and 3. In between each of the tests, the panelists waited before moving to the next solution to ascertain the taste detection. For each subsequent trial, the participants used distilled water to rinse their mouths. A small amount of the solutions was pipetted into the participants’ mouths starting from the lowest to the most concentrated solution. The result of the concentrations as reported by panelists were recorded according to Table 2.

Experiment 2: Effects of Temperature on Tastes

This experiment analyzed the effects of temperature on the perceived sweetness of the taste.


  1. 10% sucrose solution in 50ml tubes,
  2. Transfer pipette
  • Distilled water.

Procedure: In this experiment, 10% of sucrose solution was first subjected to different temperatures of 4°C, 25°C, and 49°C. A small quantity of each of the solutions exposed to different temperature was pipetted into the mouth by each participant and tasted while rinsing mouth in between the subsequent tests. The solutions were ranked according to the perceived sweetness using a scale of most sweet (1), moderately sweet (2), least sweet (3). The result of the test was recorded in Table 3.

Experiment 3: Perception of PTC and Sodium Benzoate

The perception of PTC and sodium benzoate test was carried out to determine the effects of genetics on taste.


The materials used to perform the test were the taste papers, sodium benzoate, distilled water, and PTC.

Procedure: Each of the participants, was given the papers to taste. In every test, distilled water was used to rinse the mouth by the panelists. The papers were tasted starting from the control and proceeding to the subsequent samples. All the results were recorded for the ability to taste indicated by yes or no in table 4.

Experiment 4: Adaptation of Receptors

The fundamental objective of this experiment was to analyze the adaptation of taste receptors.


  1. 3% NaCl
  2. Stop-watch

Procedure: A small amount of sodium chloride was put into the mouth and held for some seconds while recording the time at which the saltiness subsides. The result of the time in seconds at which a complete adaptation occurred was recorded in table 5.


The result of the experiments was recorded as shown in the following Tables below.

Table A: The composition of the panelists
Average age Gender Smoking Ethnic background
  Female Male Yes No White Hispanic Asian Black
52 98 8% 92% 60 32 4 4


Table 2: The lowest concentration at which the taste was detected (for Experiment 1)
  Bitter Sour Sweet Salty
Highest level 28 8 24 8
Middle level 36 24 48 44
Lowest level 28 4 25 44
Non-taster 8 64 3 4
Total 100 100 100 100


Tasters 100%
Non-tasters 0
Total 100%


Table 3: Ranking values for sweetness at different temperatures (Experiment 2)
  Ice (4°C) Room temperature (25°C) Warm temperature 49(°C)
Most sweet 44% 24% 20%
Moderate sweet 20% 56% 32%
Least sweet 36% 20% 48%
Total 100% 100% 100%


Table 4: The ability to taste PTC and sodium benzoate (Experiment 3)
Taste detection PTC Sodium benzoate
yes 72% 84%
No 28% 16%
Total 100% 100%


Table 5: Time for complete adaptation to occur (Experiment 4)
Average time (seconds) 27 Seconds



Experiment 1

  1. The primary goal of this test was to characterize the perception of the five fundamental taste qualities (sour, bitter, salty, sweetness, and salty). This was done by testing the ability to recognize and respond to the two concentrations of each stimulus and determine if these factors indicated any variation. The results of this study showed that there was a variation with all the stimuli recording a value above the threshold. More than 50 subjects perceived all the concentration. The respondents reported higher responsiveness to the solution of a high concentration of each of the stimulus than to the low one.
  2. Both the aged people and the smokers in this study reported different result indicating lower sensitivity to the stimuli. Age affects sense organs. According to Melis and Tomassini (2017), the reduced sensitivity among old people may be due to the loss of nerve endings or low mucus production which has notable effects in sensory organs. For instance, mucus is critical in enabling foo odors to take a sufficiently long timeenough in the nose to be detected by the nerve endings. On the other hand, when smoking a cigarette, the cigar produces some chemicals compounds which decrease the ability to register salty, sweet, sour and bitter tastes.
  3. All the solutions (1,2, and 3) were detected at different levels.
  4. Bitter taste (28) scored the highest level of detection followed by sweet (24). Salty (8) scored the least detection. This result indicated that human being is more sensitive to the bitterness of a substance than other initial taste components. The reason for bitter taste may be related to strong acidic compounds present in the solution.

Experiment 2

  1. The “most sweet” was recorded at Ice (4°C) represented by 44%, while the least sweet was recorded at 49(°C) which was 48%. This result implied that the influence of temperature on taste is not uniform. An increase in temperature appears to reduce the response to sweetnesses.
  2. Foods containing sugar compounds are more susceptible to temperature changes. This is because carbohydrates are degraded down into simple sugars at a high temperature making the food component sweeter at a higher temperature. In this scenario, sucrose is degraded at a higher temperature into glucose and fructose making the product sweeter.

Experiment 3

The percentage of tasters was 100% while the percentage of non-tasters was 0%. This outcome stipulates that the ethnic groups tested showed a difference from one another in their response about perceived taste intensity. The result indicated that Hispanics and African Americans rated taste perception relatively higher than non-Hispanic Whites and Asians.

Experiment 4

  1. The average time the salt took to subside was 27 seconds. This time appeared to decrease with a decrease in concentration. As saltines were dropping from a higher concentrated solution to lower concentrated solution, so was the time it took to subside.
  2. Generally, the outcome of this study reflects the importance of sensory evaluation in the food industry. Any employee in the food industry such as chefs and cooks are entitled to learn skills about sensory evaluation to enable them to produce foods of different consistency as a strategy to cope up with diversity among different people.
  3. Many factors could have an influence on each of these experiments which could easily alter the outcome of the tests. For instance, the panelists were not trained. Thus some of the people among them could not adhere to the guidelines highlighted for this experiment.








Work Cited

Melis, Melania, and Iole Tomassini Barbarossa. “Taste Perception of Sweet, Sour, Salty, Bitter, And Umami and Changes Due to L-Arginine Supplementation, As A Function Of Genetic Ability To Taste 6-N-Propylthiouracil.” Nutrients, vol.9, no.6, 2017, p.541.

Lab #4: Sensory Evaluation of Food.