Sensory Evaluation Flashcards
what are factors that can affect sensory evaluation and how should samples be served therefore?
- temperature
- volume→ samples should be served in equal parts
- samples should be served at equivalent shelf-life or time since cooking/prep
samples should be…. when served?
- should be labeled with a random 3-digit code to avoid bias
- should be served at random or in counterbalanced order meaning that if 2 samples are served, half of the subjects recieve one sample first and the other half recieves the other first
what are the methods for sensory evulation?
- hedonic test
- discriminatory tests
- duo-trio test
- triangle test
what is the hedonic test used for and how does it work?
It is measuring consumer preference or liking of a product, normally using a 9 point scale, and is commonly and widely used for measuring food acceptability. The participants are untrained consumers representing the target market, and they test multiple samples, rating their degree of liking or disliking on hedonic scale
in a 9-point hedonic scale, what does a mean score of 7 mean?
Usually indicates a highly acceptable sensory quality
the data from hedonic tests must be analyzed using?
ANOVA and tukeys test. ANOVA analyzes the differences between the means of two or more groups and checks for at least one significant difference. If there is a p value lower than 0.05, it is considereed signifcant and u proceed to tukeys test which tells u which groups are differenet.
what is a discriminatory test?
It is a test used to see whether there is a detectable difference among two or more products. It can be done to see if 2 samples are different, and is done to see if changes in ingredients, processing, packaging or storage conditions result in noticeable differences in taste, smell, texture or apperance. So its used a lot to see if a new and improved version of product is actually different and improved compared to exisiting
explain a duo/trio test
This test, tests to see if there is a difference between samples by using a reference. So the person is given a reference sample, which they know, they then are given 2 coded samples and are asked to match which coded sample matches the reference. So they have a 50% chance of correctly guessing
explain a triangle test
This test is used for detecting minor variations, more sensitive test, and is better for trained panels. So in this test people are given 3 coded samples, two are identical and one is different, and they are asked to identify the odd one out. So they have a 33.3% chance of correctly guessing
what are the steps for solving a chi square problem
- caculate expected frequencies (E): 1/3 x # of test subjects→ expected correct, 2/3 x # test subjects→ expected incorrect
- fill in the table
- compare to crtical value, calculate df: always will be 1, and critical value 3.84 and decide to accept or reject
in a chi square test, when can u accept or reject the null hypothesis
ACCEPT: when the calculated value is less than the critical value
REJECT: when the calculated value is greater than the critical value
*critical value is 0.05→3.84
