Sensory evaluation

Welcome to the World of Sensory Evaluation!

Have you ever wondered why you prefer one brand of crisps over another, or why a meal smells so good it makes your mouth water? That is exactly what sensory evaluation is all about! In this chapter, we are going to learn how to use our senses to test food and how scientists and chefs use these tests to make sure the food they sell is perfect. Don't worry if it sounds like a lot of science—it is mostly about how you experience food every single day!

1. The "Big Four" Senses in Food

When we "taste" food, we aren't just using our tongues. We use a combination of senses to decide if we like something. In your exam, you need to know how these four play a part:

Sight (Appearance): We eat with our eyes first! We look at the colour, shape, size, and how the food is garnished. If a steak looks grey instead of brown, we might assume it doesn't taste good before we even try it.

Taste (Flavour): This happens on your tongue. There are five basic tastes: Sweet, Sour, Salt, Bitter, and Umami (a savoury, meaty taste like soy sauce or parmesan cheese).

Touch (Texture/Mouthfeel): How does the food feel? Is it crunchy, smooth, chewy, or fizzy? Scientists call this "mouthfeel."

Aroma (Smell): This is huge! Our nose detects chemicals in the air. Analogy: Think about when you have a blocked nose during a cold—food tastes "boring," right? That is because your sense of smell is responsible for about 80% of what we think is flavour.

Quick Review: To remember the five basic tastes, use the mnemonic "Silly Snakes Say Bad Utterances" (Sweet, Sour, Salt, Bitter, Umami).

2. How Our Body Detects Flavour

To understand sensory testing, we need to know the "hardware" our body uses:

Taste Receptors

Your tongue is covered in tiny bumps called papillae. Inside these are your taste receptors (taste buds). When food dissolves in your saliva, these receptors send a message to your brain saying "Hey! This is salty!"

The Olfactory System

This is just a fancy name for your sense of smell. At the back of your nose is the olfactory patch. When you chew, aromas travel up the back of your throat to this patch. This is why smelling a cake baking makes you hungry!

Key Takeaway: True "flavour" is a team effort between your taste receptors on your tongue and your olfactory system in your nose.

3. Sensory Testing Methods

Companies don't just guess if people like food; they use specific tests. You need to know these three main groups:

A. Preference Tests (Do you like it?)

These are used to find out which product a consumer enjoys more.

• Paired Preference: A person is given two slightly different samples (e.g., two types of cola) and asked which one they prefer.
• Hedonic Test: Testers use a scale of "smiley faces" or scores (usually 1 to 9) to say how much they like a product, from "dislike extremely" to "like extremely."

B. Discrimination Tests (Can you tell the difference?)

These check if a change in ingredients can actually be noticed.

• Triangle Test: This is a classic! A tester is given three samples. Two are identical and one is different. The tester has to pick the "odd one out."

C. Grading Tests (How would you describe it?)

• Ranking: Testers put foods in order for a specific trait (e.g., rank these 4 crackers from 1st to 4th for "crunchiness").
• Rating: Testers give a score for a specific characteristic (e.g., "Rate the spiciness of this curry from 0 to 10").
• Profiling (Star Diagram): This creates a "map" of the food. Testers rate several traits (like sweetness, saltiness, crunch) and the results are plotted on a star-shaped web. This is great for comparing two different recipes visually!

Common Mistake to Avoid: In a Triangle Test, students often think you are testing three different things. Remember: Two are always the same! You are looking for the "imposter."

4. Setting Up a Fair Taste Panel

For sensory testing to work, it has to be a "fair test." We have to control the conditions so people aren't distracted.

The Environment:
- Quiet: No talking (so testers don't influence each other).
- Clean: No strong smells in the room (like perfume or cleaning spray).
- Lighting: Sometimes red light is used so testers can't see the colour of the food (this makes them focus only on taste!).

The Setup:
- Water/Crackers: Testers must have a sip of water or a bite of a plain cracker between samples to "cleanse the palate" (reset their taste buds).
- Coding: Never label samples "A" or "1" because people often pick those first. Use random 3-digit numbers (like 482, 915) to avoid bias.

Key Takeaway: A fair test means no talking, neutral smells, palate cleansers, and blind coding.

5. Improving Your Own Food (Practical Skill S1)

In your practical lessons, you are doing sensory evaluation every time you "taste as you go." Here is how you can modify your food based on your senses:

• To change aroma: Add fresh herbs, spices, or garlic towards the end of cooking.
• To change texture: Add a "crust" using breadcrumbs, or use browning (caramelisation) to make vegetables go from soft to crispy.
• To change taste: If a sauce is too sour, a tiny pinch of sugar can balance it. If it's bland, add a squeeze of lemon (acid) or salt.
• To change appearance: Use garnishes (like chopped parsley) or decorative techniques (like piping mashed potato) to make it look professional.

Did you know? Chefs use "reduction" (boiling a sauce to let water evaporate) to make the aroma and flavour much stronger. It’s like concentrating the "yumminess"!

Quick Review Box

1. Name the 5 basic tastes: Sweet, Sour, Salt, Bitter, Umami.
2. What is a Triangle Test? Selecting the odd one out from three samples (two are the same).
3. How do you "cleanse the palate"? Drink water or eat a plain cracker between tastes.
4. What is a Star Diagram used for? To visually show the sensory profile (multiple characteristics) of a food.