Types of Sensory Testing

Sensory evaluation is designed for a food product to determine one of the following:

1. Descriptive testing – using descriptive words in a sensory evaluation to characterize food samples.
2. Affective testing – panelists are used to determine the acceptability or preference between products.
3. Difference testing – panelists are used to determine whether detectable differences exist between products.

1. Difference Testing

Paired Comparison Test – test of difference in which a specific characteristic is designated to be evaluated in two samples. The sample with the greater level of the characteristic is to be identified.

Judge has a 50% chance of being right by chance alone.
Duo-Trio Test – difference test in which two samples are judged against a control to determine which of the two is different from the control.
Judge has a 50% chance of being right by chance alone.
Triangle Test – difference test in which 3 samples are presented (two of the samples are the same). Panelists are asked to identify the odd sample.
Judge has a 33.3% chance of guessing the right answer due to method of presentation.
Rank Order – samples are ranked in order of intensity of a specific characteristic. Valuable when several samples need to evaluated for a single characteristic.

2. Affective Testing

Hedonic Rating Scale – measures the degree of pleasure provided by specific characteristics of various food samples.
Scale can be presented using descriptive terms or visual/ picture aids (i.e., the “Smiley” scale).
The range of the scale covers a range of responses, such as unacceptable (extremely dislike) to very acceptable (like extremely), ie:

a. Preference Ranking Test

Preference ranking tests are used to rank foods in order of preference.  They are used when two or more samples are being tested.  The number of samples used is dependent on the tester’s attention span and memory.  The tester is asked to assign an order to the samples according to his / her preference.  Ranking tests do not determine the degree of liking / disliking for each of the samplesTester is presented with a number of coded samplesTester ranks samples in order of preference

b. Hedonic Rating Test

Rating tests can be used to find out how much testers like or dislike a product.  The term hedonic means having to do with pleasure so rating scales to do with likes or dislikes are called hedonic rating scales. 

1. Tester is presented with one or more coded samples
2. Tester indicates their degree of liking for each product

3. Food Action / Attitude Rating Test

In a food action rating test a scale is used to determine the attitudes of testers to a food.  It is often referred to as a “FACT Scale”.  The test can be carried out on one or more samples of food. 

1. Tester is presented with one or more food samples
2. Tester indicates their attitude to the food on prepared scales