Food & Nutritional Sciences Course 1How the Cookie Crumbles
Developing a Sensory Evaluation Instrument
List all important characteristicsNarrow list to 5 itemsDevelop a scale for each characteristic from one extreme to anotherExample: Chewiness goes from too chewy to too crunchyDraw a 10cm line and place the extremes at either end of the line.Repeat for all characteristics
Before we can collect any data, we have to have a hypothesis to test for each item.Null hypothesis always states “no difference”Alternate hypothesis states “difference”Example for chewiness:Null: There is no difference in chewiness between the original recipe and the healthy recipe.Alternate: There is a difference in chewiness between the original recipe and the healthy recipe.
Note: we didn’t state a direction of difference (chewier or crunchier)Write a hypothesis for each item.We’ll explain testing after we have data.
Measure the distance from the left side of the line to the participant’s mark on each item and write in the margin (in centimeters).The number of centimeters – with decimal values – is the data.Enter into the cell for the participant and item #.Automatically calculates significance for you.If p < 0.05, there is a difference between the cookies.
Enter all data in the spreadsheet:
Decide on a labeling plan (and stick to it!)participant numberSomething to indicate healthy or original WITHOUT revealing to participantPresent participant with on cookie on a plate & have tasteProvide form & allow them to continue tasting while completing form
Repeat with the other cookieYou need 40 participants!
The spreadsheet has formulas ready to goYou can type in the blue cells only.
If the p-value is less than 0.05, reject the null hypothesisThere is a significant difference between the cookiesIf two-tailed t-score is greater than 0.05, keep the null hypothesis.There is not a significant difference between the cookiesRepeat for all items and record your findings.
Conclusions are the decisions you make based on your results.On which items did you have a significant difference between cookies?What do you think that means about people’s cookie choices?Do you think your healthy option cookies will sell?