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What is sensory evaluation?

Sensory evaluation is a scientific discipline that analyses and measures human responses to the composition of food and drink, e.g. appearance, touch, odor, texture, temperature and taste.

Sensory evaluation can be used to:

1.  compare similarities/differences in a range of dishes/products;
2.  evaluate a range of existing dishes/food products;
3.  analyses food samples for improvements;
4.  gauge responses to a dish/product, e.g. acceptable v unacceptable;
5.  explore specific characteristics of an ingredient or dish/food product;
6.  check whether a final dish/food product meets its original specification;
7.  Provide objective and subjective feedback data to enable informed decisions to be made.

How to perform sensory evaluation

1. Decide on the type of test you want to perform – suitable for what you want to find out.

 Preference test – asks whether people like or dislike a product, e.g. hedonic scale

 Discrimination test – asks people to describe a particular attribute of a product, e.g. paired comparison test.

2. Find a clear area to hold the sensory test. Try to make sure that it is away from noise and cooking smells which may distract the people taking part in the test. This can be difficult in a busy classroom. Some schools have created areas within the food room for tasting to be held.

3. Place as many samples in serving containers as there are people taking part in the test. Code each sample with a random number, letter or symbol.

4. Check that you have enough glasses of water for the people taking part. This is for tasters to cleanse their palette after tasting each food sample.

5. Make sure the people taking part know what is expected from them, i.e. they understand which test they are taking and what they have to do.

6. Ask each person to taste one sample at a time, and record their responses. Allow time between samples so that tasters can record their opinions.

Types of tests

Preference Tests

These types of tests supply information about people’s likes and dislikes of a product. They are not intended to evaluate specific characteristics, such as crunchiness or smoothness. They are subjective tests and include hedonic, paired comparison and scoring.

Hedonic

1. Prepare the food samples.

2. Ask each taster to taste each sample in turn and tick a box, from ’1 Dislike Very Much’ to ’5. Like Very Much’ to indicate their preference. This is a 5-point-scale. Sometime a 9-point-scale is used.

3. The taster may also wish to make remarks about the products’ appearance, taste, odour and texture.

4. Analyze the results. Which sample received the highest/lowest scores? Which sample was preferred?

Paired Comparison Test (Preference)

1. Prepare two samples of the dish you wish to test.

2. Ask each taster which dish they prefer.

3. Record the response from the tasters.

Scoring

1. Food samples are scored on a scale, between dislike and like.

2. Allow tasters to evaluate samples and score (place in order of preference).

3. Record their responses.

Discrimination Tests

These types of tests aim to evaluate specific attributes, i.e. characteristics of products (crunchiness). They are objective tests and include triangle, duo trio, ranking and paired comparison.

Triangle test

1. Prepare three food samples, two of which are the same.

2. Arrange the samples in a triangle.

3. Ask the tasters to decide which of the samples the odd one out is.

4. Record the responses from the tasters.

Ranking test

1. Decide on the attribute to be ranked, e.g. crunchiness.

2. Allow tasters to evaluate samples and place them in rank order according to the presence or absence of the attribute from ‘very’ to ‘not at all’.

3. Record the responses.

Paired Comparison Test (Discrimination)

1. Prepare two different samples of the food product you wish to test.

2. Compare one attribute, e.g. which one is smoother?

3. Record the response from the tasters.

References

Sensory evaluation Teachers’ guide.