FN10: Sensory Properties of Food
How we perceive food through the senses: appearance, aroma, taste, texture, and flavour. Sensory evaluation methods and their use in food product development.
Sensory Properties of Food
How we perceive food through the senses: appearance, aroma, taste, texture, and flavour. Sensory evaluation methods and their use in food product development.
Key Fact: Sensory properties are how we perceive food through our five senses: sight (appearance/colour), smell (aroma), taste, touch (texture/mouthfeel), and hearing (sound — crunch, sizzle).
Key Fact: The five basic tastes: sweet (sugar), salty (salt), sour (acids — lemon, vinegar), bitter (coffee, dark chocolate), umami (savory — MSG, soy sauce, parmesan, tomatoes, Marmite).
Key Fact: Flavour is a combination of taste (on the tongue) and aroma (detected by the olfactory receptor in the nose). Up to 80% of what we perceive as 'flavour' actually comes from aroma, not taste.
Key Fact: Texture and mouthfeel: crispiness, crunchiness, chewiness, smoothness, softness, flakiness, crumbliness, juiciness, stickiness. Texture is perceived through touch receptors in the mouth and jaw.
Key Fact: Appearance: colour, shape, size, surface texture, and presentation. We eat with our eyes first — appearance creates expectations about flavour and quality. Colour changes during cooking indicate chemical changes (browning, loss of green colour).
Key Fact: Aroma: detected when volatile compounds reach the olfactory receptors. Aromas can be orthonasal (sniffed through the nose) or retronasal (released during chewing, travelling from mouth to nose). Retronasal aroma is the main contributor to flavour perception.
Key Fact: Sensory evaluation: objective methods used by the food industry to assess food products. Types: preference tests (which do you prefer?), discrimination tests (can you tell the difference?), and profiling (describe the characteristics).
Key Fact: Star/radar diagram: a visual tool for comparing sensory attributes of products. Each spoke represents an attribute (sweetness, saltiness, crunch, etc.), rated on a scale. The resulting shape shows the sensory profile. Useful for comparing products or evaluating improvements.
Key Fact: Paired comparison test: two samples presented simultaneously — which is sweeter/crisper/preferred? Triangle test: three samples (two identical, one different) — identify the odd one out. Used for quality control and product development.
Key Fact: Hedonic rating scale: a preference scale from 1 (dislike extremely) to 9 (like extremely). Used in consumer testing to assess acceptability of products.
Key Fact: Sensory evaluation conditions: controlled environment (neutral lighting, individual booths, no strong smells), coded samples (to avoid bias), palate cleansers between samples (water, plain crackers), randomised sample order.
Key Fact: Factors affecting sensory perception: age (taste buds decline), hunger level, cultural background, previous experience, health (colds reduce aroma perception), and expectations (brand, packaging, price influence perceived quality).
📋 Key Vocabulary and Concepts
For Sensory Properties of Food, you must know:
- Sensory evaluation
- Star/radar diagram
- Hedonic scale
- Paired comparison
- Triangle test
- Umami
- Retronasal aroma
- Orthonasal aroma
- Mouthfeel
- Preference test
- Discrimination test
- Profiling
- Palate cleanser
- Sensory attribute
❓ Practice Questions
Q: Explain the difference between taste and flavour.
Q: Describe how a star diagram is used in sensory evaluation.
Q: Evaluate the importance of sensory evaluation in food product development.
✅ Answers
- Taste is detected by taste buds on the tongue — there are only five basic tastes (sweet, salty, sour, bitter, umami). Flavour is a combination of taste AND aroma (detected by the olfactory receptors in the nose). Up to 80% of flavour perception comes from aroma released during chewing (retronasal). This is why food seems tasteless when you have a cold — blocked nasal passages prevent aroma detection.
- A star diagram (or radar chart) plots sensory attributes on spokes radiating from a centre point. Each spoke represents one attribute (sweetness, crunchiness, saltiness, etc.), rated on a scale (typically 1-5). Points are connected to form a shape that represents the product's sensory profile. Comparing two or more star diagrams allows visual comparison of products — overlapping areas show similarities, differences show where products diverge.
- Sensory evaluation is essential because it provides objective data on how consumers perceive products, guiding development decisions. Without it, products might fail in the market despite being nutritionally sound. However, sensory testing has limitations: small sample sizes may not represent all consumers, controlled conditions differ from real eating environments, and cultural/preferences vary. It should complement nutritional analysis and market research, not replace them.
🎯 Exam Tips
- Use the correct terminology: 'aroma' not 'smell', 'mouthfeel' not 'texture in the mouth'
- Always explain how sensory tests are conducted, not just their names
- Link sensory properties to food science — e.g. browning = Maillard reaction, soft texture = gelatinisation
📝 Exam Technique
Food Preparation & Nutrition Exam Tips — Sensory Properties of Food:
1. For Sensory Properties of Food questions, show every step of your working clearly — method marks count even if the final answer is wrong
2. Check your answer makes sense in context (estimation, units, reasonableness)
3. Use correct mathematical notation and state formulae before substituting values
4. If a Sensory Properties of Food question asks you to 'prove' or 'show', write a logical chain of reasoning with a conclusion line
5. For problem-solving, identify the topic first, then recall the relevant method
1. For Sensory Properties of Food questions, show every step of your working clearly — method marks count even if the final answer is wrong
2. Check your answer makes sense in context (estimation, units, reasonableness)
3. Use correct mathematical notation and state formulae before substituting values
4. If a Sensory Properties of Food question asks you to 'prove' or 'show', write a logical chain of reasoning with a conclusion line
5. For problem-solving, identify the topic first, then recall the relevant method
⚠️ Common Errors
✗ Taste and flavour are the same thing. ✓ Taste is detected only on the tongue (5 basic tastes). Flavour combines taste AND aroma — most of what we perceive as flavour actually comes from aroma detected by the olfactory receptors in the nose.
✗ There are only four basic tastes. ✓ There are five basic tastes: sweet, salty, sour, bitter, and umami (savory). Umami was identified as a distinct taste in 1908 by Kikunae Ikeda, who isolated glutamate as its source.
✗ Sensory evaluation is just someone's opinion. ✓ Sensory evaluation uses controlled, scientific methods to produce reliable data. Conditions are standardised (lighting, booths, sample coding, palate cleansers), multiple testers are used, and statistical analysis identifies significant differences. It is objective, not subjective.
✍️ Model Answer
Full-Mark Response
Explain how sensory evaluation methods can be used to develop a new food product. [12 marks]
Sensory evaluation plays a crucial role at every stage of new product development, from concept to launch. At the concept stage, profiling identifies the desired sensory characteristics. A star diagram maps the target profile — for example, a new snack might target high crunch, medium saltiness, low sweetness, and strong umami. This provides a clear sensory specification for development. During development, discrimination tests (triangle or paired comparison) assess whether recipe changes are detectable. If a manufacturer replaces an ingredient (e.g. reducing salt), they need to know if consumers can tell the difference. Triangle tests identify the minimum change that remains acceptable. Preference testing uses hedonic scales (1-9) to determine which version consumers prefer. Multiple prototypes are tested with target consumers to identify the recipe with the highest acceptability. This is more useful than expert assessment because consumer preferences ultimately determine market success. Star diagrams compare prototypes visually. If the target profile specifies high crunch but the current version scores low, the developer knows to adjust cooking time or ingredient ratios to increase crunchiness. At the final stage, large-scale consumer testing validates the product with the target market. Controlled conditions (individual booths, coded samples, palate cleansers) ensure reliable results. Statistical analysis confirms whether differences are significant. However, sensory evaluation has limitations: controlled test conditions differ from real consumption contexts; small panels may not represent all consumers; and sensory data alone doesn't predict commercial success, which also depends on price, packaging, and marketing. Overall, sensory evaluation is essential for product development but should be one component of a broader development process including nutritional analysis, cost optimisation, and market research.
📊 AO Deep Dive
Assessment Objective Analysis
AO1 (Knowledge & Understanding): Demonstrate knowledge and understanding of sensory properties of food, including nutritional principles, food science, and food safety regulations.
AO2 (Application): Apply knowledge and understanding of sensory properties of food to practical cooking contexts, recipe adaptation, and food choice decisions.
AO3 (Analysis & Evaluation): Analyse and evaluate sensory properties of food in relation to nutritional needs, food safety, sustainability, and cultural factors. Justify decisions with reasoned arguments and evidence.
📝 Exam Questions by Topic
- AQA Past Papers - Topic Questions -- AQA
- Edexcel Past Papers - Topic Questions -- Edexcel
- OCR Past Papers - Topic Questions -- OCR
- Eduqas Past Papers - Topic Questions -- Eduqas
🎬 Video Resources
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