What they have in common is that they are all sugars and therefore carbohydrates. Within the carbohydrates there are three families: sugars, oligosaccharides and polysaccharides. All these '-oses' belong to the family of sugars and which in turn is divided into monosaccharides (single saccharides or simple carbohydrates) and disacharids (a chain of two saccharides). The classification is thus based on the molecular structure of the carbohydrates: oligosaccharides have 3 to 9 monosaccharides, polysaccharides have 10 or more. Starch, for example, is the main polysacharide, it consists of long chains of glucose molecules.
Monosacharides are thus simple building blocks (monomers) that exist on their own or in duo, but which also serve as the basis for more complex carbohydrates namely the oligo and polysaccharides. Each of these molecular structures has a different effect on the rise in blood sugar (blood glucose) and metabolism.
Glucose and dextrose
When we talk about 'glucose', it normally means the D-glucose (D stands for dexter which means on the right). In addition, there is another species, the L-glucose (L stands for laevus which means left). D-glucose is the natural form of glucose, L-glucose is made synthetically. Another name for D-glucose is dextrose or grape sugar.
D-glucose (or dextrose) is the most common monosacharide and it is an important fuel for the metabolism of humans and animals. Glucose is absorbed into the blood faster than sucrose and fructose and therefore gives an immediate energy boost. It is also a reference point for determining the glycemic index* of carbohydrates: the GI of glucose is 100.
Glucose can be easily released from starch. Starch is broken down in our digestive system into glucose that enters our blood via the small intestine, where it circulates like blood sugar. Through the blood it is transported to our cells and there it is absorbed with the help of proteins. The hormone insulin also plays an important role in this process. The glucose, which is not converted into energy, transforms into glycogen and is stored in the liver and muscles.
In the food industry, dextrose is often used in hard candy (lollipops, acids...). It mixes very well with water; it binds with it in the form of a solid substance. Since dextrose is absorbed very quickly into the blood, it is also used in energy tablets.
Glucose is slightly less sweet than sucrose, but it has the same energy value: 100 g of glucose contains 400 kcal.
* The glycemic index (GI) indicates how quickly carbohydrates are absorbed into the blood. People with diabetes are recommended to eat foods with a low or medium glycemic index (GI) because it keeps their blood sugar levels more stable.
In addition to the GI, the GL (glycemic load) is also an important parameter because it takes into account the average portions you eat of a product and its effect on blood sugar levels.
Fructose
Fructose is the scientific name for fruit sugar or fruit sugar and it is also a monosacharin. It occurs naturally in fruit, honey and to a lesser extent in vegetables. Fructose is processed more slowly in the body, its glycemic index is 19.Fructose is as tasty as sugar, cheaper and because its sweetening power is almost twice as large, the required amount also yields fewer kilocalories. Cheap glucose syrup can be converted into fructose via an enzyme, and large soft drinks companies like to use that process.
In the food industry it is not only used in soft drinks and fruit juices, but also in bread toppings, sweetened milk products/yoghurt and even in ready-made sauces such as ketchup. In some people, an excess of fructose through these sources gives rise to intestinal complaints: diarrhoea, abdominal pain and/or bloating. Fructose in processed products is also no better or healthier than sugar. It even disrupts fat metabolism.
Although it has the same energy value of glucose, it is almost twice as sweet. 100 grams of fructose contains 400 kcal.
Lactose
Lactose is naturally present in mammalian milk and is therefore also called milk sugar. It is therefore in all products derived from it: all types of milk (goat, cow, horse), yoghurt and cream, custard, buttermilk and porridge. It also occurs in a number of cheeses: cottage cheese,melt cheese, cheese spread and cottage cheese (also called Hüttenkäse).
Lactose is a disacharide composed of glucose and galactose (another monosacharide). If you are lactose intolerant, you don't have enough lactase in the small intestine. That's an enzyme needed to digest the lactose.
The energy value of lactose is 44 kcal per 100 grams. Its glycemic value is 46.
Sucrose en sacharose
What we call 'sugar' is actually another name for sucrose, also called sucrose. It is refined from sugar beet or cane sugar and it is a disacharide composed of a glucose and a fructose molecule. So there is no difference in composition between beet sugar and cane sugar. In both cases, sucrose is involved.
Both building blocks of sucrose (glucose and fructose) can be disconnected by hydrolysis using an enzyme. This is a technique used, among other things, to give chocolates a soft, creamy filling.
The glycemic index of sucrose is 65. The energy value is the same as with glucose and fructose, which is 400 kcal per 100 grams, which makes sense since it is composed of those two molecules.
What about honey? Honey is a mixture of glucose and fructose and therefore also a form of sugar. It does contain more water than granulated sugar and therefore its energy value is also somewhat lower: about 300 kcal per 100 grams.
