All foods mostly consist of just four types of molecules: Carbohydrates, proteins, fats and water. In this Science series I will explain a bit more about each of those elements. This article is, as the title suggests, all about carbohydrates. Let's get learning!
Everyone has heard of carbs or carbohydrates. Some people read about them in articles on why you should avoid them, some remember them from a biology class you had and for other people it might be daily business by for example counting macros. But what are they and what do they do?
All carbohydrates consist of one or more sugar molecules (saccharides). These molecules all have a 5 or 6 ring with carbon (the carb in the carbohydrate), hydrogen and oxygen atoms. The molecules can be connected in a long string kind of way and sometimes they have branches. The length and complexity (branched or not) determines whether your body can break it down and if so, how easily it can be broken down.
When you eat something containing carbohydrates your body first needs to break them down into simple molecules to be able to absorb them in your intestines. If the molecule is long and complicated it will take more energy and time for it to break down and thus it takes longer before your body can actually use the energy of the molecule.
Let's take glucose, the most well known and basic sugar molecule. It is a 1 molecule carbohydrate and thus called a monosaccharide (mono means 1). Your body doesn't need to break down the molecule because it can be absorbed and used for energy as it is. This is why these kind carbohydrates are also called simple carbs.
These are some monosaccharide examples:
If we take a carbohydrate of two molecules it is called a disaccharide (di means 2). These require more work to be broken down. This is done by enzymes which (simply said) cut off either the end of the moleculestring or cut in the middle of a string. That way two separate molecules are formed which can be absorbed by your body and used for energy.
One of those disaccharides is lactose. Lactose consists of a glucose and galactose molecule. If you have a lactose intolerance, you miss the enzyme lactase which would cut the molecule. The uncut lactose then travels further into your intestine where it is "eaten" by bacteria, which produce gas.
On to the even bigger carbohydrates: Oligosaccharides and polysaccharides! Oligosaccharides contain between 3- 10 molecules and poly means many or much and polysaccharides thus consist of lots of molecules. They take longer to be broken down and are referred to as complex carbs. Two examples of polysaccharides are amylose and amylopectin. Amylose is an unbranched molecule, where amylopectin is a branched molecule. Both again are broken down by enzymes into smaller molecules. One of those enzymes is amylase.
Polysaccharides are able to hold water and can be used as thickeners. I have a small (slightly weird) experiment you can do. You will need a small ramekin, a spoon and custard (or in Dutch "vla") which is made with starch. Add a spoon of custard to the ramekin and stir. Notice how thick it is. Now add some saliva to the custard in your ramekin and stir again. Do you see it is becoming thinner? This is the amylase in your saliva which is starting to break down the starch.
Now we know what they look like on a molecular level, what function do they actually have? Firstly they provide you with energy: 4 kcal/ gram.
Secondly they can add to how you experience the food (sensory):
Sweet flavour: Like sugar in your tea
Sweet scent: The sweetness you smell when baking cookies
Colour by caramelisation or the Maillard reaction: The golden brownness of your cake or literal caramel
Texture of the food: Think about crunchy sugar crystals or thickening like in custard.
Not all carbs are equal, so not all contribute to all 4 sensory elements. Like pasta: this doesn't smell or taste sweet and it doesn't have the golden brown colour due to heating. The carbs in the pasta are there to provide texture.
That was it for the carb information for now. Ready to put it to the test? Head over here for a tangy lemon drizzle and see if you can sense all the influences of the carbohydrates.
If you have any questions, please leave a comment :).