How the senses work together to judge food, the purpose of sensory evaluation, and the main sensory testing methods (preference, discrimination and ranking or rating tests) and how to carry them out fairly.

What this dot point is asking

AQA wants you to explain how the senses judge food, why food companies and cooks use sensory testing, the main test types, and how to run a test fairly so the results are valid and reliable.

How the senses judge food

Why we use sensory testing

Food manufacturers and cooks use sensory evaluation to develop new products, improve recipes, check quality and consistency batch to batch, and compare their product with a competitor's. It is part of product development: a manufacturer tests prototypes on a target consumer panel before spending money launching a product, reducing the risk of an expensive failure. Results are also used to set a quality standard so that every batch tastes, looks and feels the same.

The main test methods

A star profile plots scores for several attributes (such as sweetness, saltiness, crunch and colour) on a spider chart, so two products can be compared shape against shape at a glance. A ranking test simply puts samples in order for one attribute, for example from least to most spicy. Choosing the right test depends on the question: use discrimination to check if a cheaper ingredient changes the product, preference to check which version consumers want, and rating or ranking to profile specific qualities.

Carrying out a fair test

To make results valid and reliable, control the conditions:

• Use identical, coded containers with random three-digit codes (not 1 and 2, which suggest an order or ranking).
• Serve samples at the same temperature, size and amount so only the recipe differs.
• Provide water or a plain cracker to cleanse the palate between samples.
• Test in a quiet, well-lit, odour-free area, with tasters working independently so they do not influence each other.
• Use a clear recording chart and enough tasters for reliable results, then average or tally the scores.

Validity means the test measures what you intend (the food, not the setup); reliability means you would get the same result if you repeated it. Random coding, identical presentation and independent tasting are the controls that protect both.

Try this

Q1. Name the five senses used in sensory evaluation. [2 marks]

• Cue. Sight, smell, taste, touch and hearing.

Q2. Explain why samples are given random codes rather than being labelled 1 and 2. [2 marks]

• Cue. To avoid bias, as numbers like 1 and 2 could suggest an order or preference to the taster.