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| What is the threshold test? How do I do it? | to Top |
Essentially the threshold test determines the sensitivity of the panelist to a particular test. Following is the general way that this webber sets up the threshold test in the classroom. It is a simple approach. TASTE THRESHOLD EXPERIMENT Purpose:
1. To determine difference and recognition thresholds for sweet and sour for women volunteers.
2. To determine whether there is a correlation between thresholds for sweet and sour in the volunteers.
3. To determine whether there is a correlation between thresholds for sweet and sour and ability to rank a homogenous food (applesauce) varying in concentration of (a) sucrose and (b) citric acid.
Procedure:
Water solutions of sucrose will be used to determine the threshold for sweet, and water solutions of citric acid for measurement of thresholds for sour.
A. Preparation of Solutions. Use sterilized demineralized distilled water to prepare all solutions.
Sucrose: Stock Solution=0.1M Weight out 34.2 gm of sucrose. Dissolve in clean dry beaker (250mL) and make to 1 liter in glass stoppered mixing cylinder. Mix thoroughly.
Citric Acid Stock Solution=0.1M Weight out 21.01 gm of citric acid monohydrate in clean, dry beaker (250 mL) and make to 1 liter in glass stoppered mixing cylinder. Mix thoroughly.
Test Solutions
Sucrose
| Solution Number | Molar,br>Concentration | Dilution |
| 1 | .001 | 5 mL of stock-->500 |
| 2 | .004 | 20 mL of stock-->500 |
| 3 | .007 | 35 mL of stock-->500 |
| 4 | .01 | 50 mL of stock-->500 |
| 5 | .015 | 75 mL of stock-->500 |
| 6 | .02 | 100 mL of stock-->500 |
| 7 | .03 | 150 mL of stock-->500 |
| 8 | .04 | 200 mL of stock-->500 |
| 9 | .05 | 250 mL of stock-->500 |
| Solution Number | Molar Concentration | Dilution |
| 1 | .00025 | 1.25 mL of stock-->500 |
| 2 | .0005 | 2.5 mL of stock-->500 |
| 3 | .001 | 5 mL of stock-->500 |
| 4 | .002 | 10 mL of stock-->500 |
| 5 | .004 | 20 mL of stock-->500 |
| 6 | .007 | 35 mL of stock-->500 |
| 7 | .01 | 50 mL of stock-->500 |
| 8 | .015 | 75 mL of stock-->500 |
| 9 | .02 | 100 mL of stock-->500 |
Administering Tests
Put 10 mL of sample in 3-oz juice or 1 oz shot galsses. Arrange samples on trays in increasing concentration. Have judge taste water first and then samples. Allow 15 seconds, stop-watch time, between tasting. Have judge continue until he correctly identifies the basic taste two times in succession. The lower of the two will then be considered the recognition threshold. Analysis of Data
Simple correlation of taste thresholds for sucrose and citric acid solution, using the lowest number of each solution correctly identified by each judge.
Updated: Saturday, December 29, 2007.
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