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This lesson covers the practical aspects of setting up and conducting sensory evaluation tests, including taste panels, controlled conditions and evaluating sensory qualities, as required by the AQA GCSE Food Preparation and Nutrition specification (8585), section 3.5.
For sensory evaluation results to be reliable and valid, the testing conditions must be carefully controlled. Without controlled conditions, results may be biased or inconsistent.
| Principle | How to Achieve It |
|---|---|
| Consistent samples | Each taster receives the same amount, at the same temperature, presented in the same way |
| Random coding | Samples labelled with random three-digit numbers (e.g., 247, 391, 582) — not letters or names that might bias the taster |
| Controlled environment | Testing in a quiet, well-lit room free from distractions |
| Independent assessment | Each taster works individually without discussing opinions with others |
| Palate cleansing | Tasters cleanse their palate between samples |
| Sufficient tasters | A large enough sample of tasters to produce meaningful results |
| Random order | The order in which samples are presented varies between tasters to avoid order bias |
A taste panel is a group of people who evaluate food samples. There are two main types:
| Feature | Detail |
|---|---|
| Who | Members of the general public or potential consumers |
| Training | None — they give personal opinions based on their own experience |
| Best for | Preference tests (paired preference, hedonic) and market research |
| Size | Typically 30–100+ people for reliable results |
| Advantage | Represents real consumer opinion; easy to recruit |
| Limitation | Inconsistent — different people interpret scales differently; personal biases |
| Feature | Detail |
|---|---|
| Who | Selected individuals who have been trained in sensory evaluation techniques |
| Training | Trained to recognise specific flavours, textures and aromas; calibrated in their scoring |
| Best for | Discrimination tests (triangle test) and grading tests (rating, profiling) |
| Size | Typically 6–12 people |
| Advantage | More consistent and objective results; can detect subtle differences |
| Limitation | Expensive and time-consuming to train; may not represent typical consumer opinion |
flowchart TD
A["Taste Panels"] --> B["Untrained Panel<br/>30-100+ people"]
A --> C["Trained Panel<br/>6-12 people"]
B --> D["Preference tests<br/>Consumer opinion<br/>Market research"]
C --> E["Discrimination tests<br/>Quality control<br/>Sensory profiling"]
style B fill:#3498db,color:#fff
style C fill:#e67e22,color:#fff
| Feature | Requirement | Why |
|---|---|---|
| Testing booths | Individual booths or partitions to separate tasters | Prevents tasters influencing each other through facial expressions, comments or body language |
| Neutral lighting | White or neutral lighting (or specified colour) | Coloured lighting can mask the true appearance of food; red lighting is sometimes used to disguise colour differences when testing flavour only |
| Quiet environment | Minimal noise and distractions | Distractions affect concentration and the ability to focus on sensory qualities |
| Room temperature | Comfortable, consistent temperature | Extreme temperatures affect taste perception |
| Odour-free | No strong smells in the testing area | Background odours interfere with aroma assessment |
| Clean surfaces | All surfaces and equipment clean and neutral | Residual flavours or smells from previous tests could contaminate results |
| Feature | Requirement | Why |
|---|---|---|
| Identical containers | All samples in the same type, colour and size of container (usually white) | Different containers may suggest quality differences |
| Random three-digit codes | Each sample labelled with a random number (e.g., 427, 815) | Prevents bias from alphabetical or numerical order; letters like A, B, C imply quality ranking |
| Equal portions | Same amount of each sample | Different amounts might suggest one is more important or better |
| Same temperature | All samples served at the same temperature | Temperature affects flavour perception — warm food tastes different from cold food |
| Same preparation | All samples prepared using the same method and equipment | Variations in preparation could introduce differences unrelated to the test variable |
Between tasting each sample, tasters should cleanse their palate to remove residual flavours:
| Cleanser | When Used |
|---|---|
| Plain water | Standard palate cleanser; room temperature; most common |
| Plain crackers or bread | Neutral flavour; absorbs residual oils and flavours |
| Apple slices | Effective between strongly flavoured samples |
| Warm water | Can be more effective than cold water for fatty or oily foods |
The taster should:
Exam Tip: Always mention palate cleansing and coded samples when describing how to set up a sensory test. These are key marks in exam answers. The reason for random three-digit codes (not A, B, C) is to prevent order bias — tasters may assume the first sample (A) is the "standard" or the best.
When evaluating food, tasters assess multiple sensory characteristics:
| Quality | What to Assess |
|---|---|
| Colour | Is it the expected colour? Is it even or patchy? Is it appealing? |
| Shape | Is it the expected shape? Is it uniform? |
| Size | Is it the expected size? Are portions consistent? |
| Gloss/Matt | Is the surface shiny or dull? |
| Garnish/Decoration | Is it well-presented? Is the garnish appropriate? |
| Overall appearance | Does it look appetising? Would you want to eat it? |
| Quality | What to Assess |
|---|---|
| Intensity | How strong is the smell? |
| Pleasantness | Is the aroma appealing? |
| Specific aromas | Can you identify specific ingredients (e.g., vanilla, garlic, cinnamon)? |
| Off-smells | Are there any unpleasant or unexpected odours? |
| Quality | What to Assess |
|---|---|
| Basic tastes | Sweet, sour, salty, bitter, umami — which are present and how strong? |
| Flavour balance | Are the flavours balanced or does one dominate? |
| Flavour intensity | Is the flavour strong enough? Too strong? Too weak? |
| Aftertaste | What flavour remains after swallowing? Is it pleasant? |
| Spiciness/Heat | If applicable, how spicy is it? |
| Quality | What to Assess |
|---|---|
| Crunchy/Crispy | Does it have a satisfying crunch? |
| Soft/Smooth | Is it smooth and tender? |
| Chewy | Does it require prolonged chewing? |
| Crumbly | Does it break apart easily? |
| Creamy | Is it rich and smooth in the mouth? |
| Moist/Dry | Is there appropriate moisture? |
| Gritty/Grainy | Is the texture rough or sandy? |
Tasters need an appropriate vocabulary to describe food qualities. Using consistent sensory descriptors helps ensure results are meaningful:
| Category | Example Descriptors |
|---|---|
| Appearance | Golden, pale, even, patchy, glossy, risen, flat, cracked, uniform |
| Aroma | Fragrant, spicy, herby, sweet, smoky, fresh, musty, burnt |
| Taste | Sweet, tangy, salty, bitter, bland, rich, sharp, mild, savoury |
| Texture | Crunchy, flaky, moist, dense, light, airy, chewy, smooth, crumbly |
| Mouthfeel | Creamy, gritty, oily, fizzy, dry, coating, refreshing, warming |
A well-designed recording sheet should include:
| Method | Best For |
|---|---|
| Tally chart | Counting preferences (paired preference test) |
| Bar chart | Comparing scores across multiple products |
| Star diagram (radar chart) | Showing sensory profiles of products |
| Table | Summarising numerical data from rating tests |
| Line graph | Showing trends (e.g., changes in a product over time) |
| Average scores | Summarising rating test data for comparison |
Star diagrams are particularly useful for comparing the sensory profiles of two or more products on the same chart:
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