Introduction: Why Sensory Properties Matter
Have you ever wondered why we love the sound of a crunchy potato crisp or why the smell of fresh bread makes us feel hungry? This is all because of sensory properties! In this chapter, we’ll explore how our five senses work together to help us enjoy and choose food. We will also look at how cooking changes these properties and how food experts test their products to make sure they are perfect for us to buy. Don’t worry if some of the terms like "organoleptic" sound a bit strange at first—once we break them down, they are very easy to understand!
1. Our Sensory Systems: The Five Senses
When we talk about the organoleptic properties of food, we just mean the qualities that we can experience through our senses. Scientists and chefs use these five senses to judge if a food is high quality.
Sight (Appearance): This is the first sense we use. If food looks burnt or a strange colour, we might not want to eat it. We look at the colour, shape, size, and even the shine (glaze) of the food.
Smell (Aroma): Our nose can detect thousands of different smells. When food is heated, the smells (vapours) are released, which is why hot food often smells stronger than cold food.
Taste: This happens on our tongue. While we often say "this tastes like strawberry," that is actually a mix of taste and smell. Our tongue itself only detects five specific tastes (see the next section!).
Touch (Texture/Mouthfeel): This is how food feels in our hands and inside our mouth. Is it crunchy, smooth, slimy, or chewy? We call this mouthfeel.
Hearing (Sound): The sound food makes when we bite it tells us a lot. A "snap" of a biscuit or the "crunch" of a carrot tells us the food is fresh and not soggy.
Quick Review: The 5 Senses
• Sight = Appearance
• Smell = Aroma
• Taste = Flavour on the tongue
• Touch = Texture/Mouthfeel
• Hearing = Sound
Key Takeaway: We eat with all our senses, not just our mouths! If one sense is "off" (like a soggy chip that doesn't crunch), the whole eating experience changes.
2. The Five Basic Tastes
Our tongues are covered in tiny receptors that can recognise five specific basic tastes. It’s important not to confuse "taste" with "flavour" (flavour is a mix of taste and smell).
1. Sweetness: Usually comes from sugars. It’s a taste we are naturally drawn to because it provides energy.
2. Sourness: Think of lemons or vinegar. A little bit adds "brightness" to food, but too much can be unpleasant.
3. Saltiness: From salt (sodium chloride). It enhances other flavours in food.
4. Bitterness: Found in things like dark chocolate, coffee, or spinach. Some people find this an "acquired taste."
5. Umami: This is a Japanese word for a savoury, meaty taste. You find it in foods like mushrooms, aged cheese, soy sauce, and grilled meats.
Memory Aid: The "S.S.S.B.U" Mnemonic
To remember the five tastes, think of: Some Salty Snacks Bring Umami.
(Sweet, Salt, Sour, Bitter, Umami)
Key Takeaway: There are only five basic tastes. Everything else we think we "taste" is actually our sense of smell helping out!
3. How Cooking Changes Food
When we cook food, we aren't just making it safe to eat; we are improving its sensory properties. Here is how food changes during the cooking process:
Texture: Cooking can make food softer (like boiling a potato) or firmer (like poaching an egg until the protein coagulates). It can also make things crispy (like frying bacon).
Appearance and Colour: Raw meat turns from pink/red to brown. Bread turns from pale dough to golden brown through a process called dextrinisation (when starch is heated and turns to sugar, then browns).
Taste and Aroma: Flavours often become more intense. Think of how a raw onion tastes sharp and "burns," but a fried onion becomes sweet and smells delicious. This browning also adds a new "cooked" flavour.
Sound: Deep-frying a piece of chicken gives it a crunchy coating that wouldn't be there if it were raw.
Common Mistake to Avoid: Many students think "flavour" and "aroma" are the same thing. Remember: Aroma is what you smell with your nose, and Flavour is the total experience of taste and smell combined.
4. Sensory Testing and Panels
Food companies use sensory testing panels to check their products. This isn't just people eating for fun; it is a controlled scientific test!
How to Set Up a Fair Test:
To make sure the results are accurate, a testing panel must follow these rules:
• Privacy: Tasters should be in separate booths so they don't see each other's faces or talk.
• Clean Palate: Tasters should drink water between samples to wash away the previous taste.
• Coding: Samples should be given random 3-digit codes (like 482 or 917) so the taster doesn't know which brand is which.
• Quiet: No talking allowed!
Styles of Testing:
Rating Tests: Tasters give a score (e.g., 1 to 5) for a specific quality, like "How crunchy is this?"
Ranking Tests: Tasters are given several samples and must put them in order, for example, from the least sweet to the most sweet.
Profiling (Star Diagrams): This is a more detailed way to look at food. Tasters rate different "descriptors" (like spiciness, saltiness, crunchiness) and the results are plotted on a star diagram. This creates a "map" of the food's sensory profile.
Key Takeaway: Sensory testing must be a "fair test." Using water to cleanse the palate and separate booths ensures the results are reliable.
5. Improving and Manipulating Sensory Properties
As a cook, you can "judge and manipulate" (change) food to make it better. Here is how:
Tasting and Seasoning: You should always taste your food as you cook. Adding a pinch of salt or a squeeze of lemon (acid) can balance out the flavours.
Infusions: You can add aroma and flavour by soaking herbs, spices, or lemon zest in liquids like milk or oil. This is called an infusion.
Changing Texture: You can add a crust or crumbs to soft fish to give it a "crunchy" mouthfeel. You can also use glazing (brushing with egg or milk) to give pastries a shiny, golden-brown look.
Presentation and Styling: We "eat with our eyes" first! You can improve the look of food by:
• Using garnishes (like a sprig of parsley or a slice of lemon).
• Thinking about portioning so the plate isn't too crowded.
• Using different decorative techniques like piping mashed potato or drizzling sauces (a jus or reduction).
Did You Know?
The colour of the plate can change how we think food tastes! Most people find food tastes better on a white plate because the colours of the food stand out more clearly.
Key Takeaway: Small changes like adding herbs, a glaze, or a garnish can turn a boring meal into a professional-looking dish.
Quick Review Quiz
1. What does the word organoleptic mean? (Qualities we sense: look, smell, taste, touch, sound).
2. Which sense tells us if a biscuit is fresh? (Hearing/Sound).
3. Name the five basic tastes. (Sweet, Sour, Salt, Bitter, Umami).
4. Why do tasters drink water between samples? (To cleanse the palate/wash away previous tastes).
5. What is dextrinisation? (The browning of starch when dry heat is applied).