Natural honey has a complex and heterogeneous composition, the components of which are directly dependent on the type of vegetation, the soil, the weather conditions, the breed of bees and their strength, the conditions under which the nectar is collected, some additional actions on the part of the beekeeper and many others. For example, Dobrudzha’s sunflower honey might differ in composition from the same kind of honey produced in the region of Yambol.
For faster reading, see the abridged version of this publication.
Summing up the composition of honey by using comparative tables is a complicated and strenuous process both because of the possible fluctuations in the components of the same varieties of honey and the great variety of honey types. You could easily conclude that a jar label gives you just some general information about the actual chemical composition of honey, which is rather insufficient.
Most generally, honey contains: carbohydrates, water, mineral substances, nitrogenous compounds, alkaloids, biogenic stimulators, plant antibiotics (phytoncides), enzymes (ferments), organic acids, essential oils, aromatic, volatile, hormonal substances, antioxidants, anti-cancer and anti-tumor agents and others that are still unknown or poorly studied.
They constitute the greater part of the dry matter of honey (the water content in honey varies between 14%-20%).
1 kilogram of honey contains 3150 - 3350 calories.
By the middle of the last century, honey was considered to be a simple mixture of glucose, fructose, sucrose (table sugar) and another vaguely defined carbohydrate honey component known as "dextrin". With the introduction of new technologies for the separation and analysis of sugars, some scientists from Europe, USA, Japan have identified a number of other sugars in honey, after successfully separating them from the complex carbohydrate mixture.
The carbohydrates in honey are divided into:
Fructose and glucose are present in the greatest percentage both in the carbohydrate composition and in the overall composition of honey. They comprise the invert sugar in honey that reaches up to 80% (with some types of honey it might go up to 90% - Jonathan White). Honey crystallization processes are greatly dependent on the proportion between those two monosaccharides.
In some sources, they are referred to as dextrose or grape sugar (which stands for glucose) and levulose or fruit sugar (for fructose).
Monosaccharides are simple sugars. They are the structural elements (the building blocks) of complex sugars - di- and polysaccharides. Complex sugars in the body should decompose to simple ones in order to be assimilated.
The greater the percentage of glucose and fructose (invert sugar), the better the quality of honey. Adulterated honey always contains less invert sugar.
In most varieties of honey fructose is present in greater amounts than glucose. However, there are some exceptions, as is the case with the rapeseed honey. Usually fructose varies between 33% and 44%, and glucose – between 25% and 40%.
Nectar, resp. honeydew in the honeydew honey, is one of the sources of the invert sugar in honey. Sucrose is another source. After the invertase enzyme has been added by bees, sucrose decomoposes in the process of honey maturing.
Fructose is sweeter then sucrose (known as "table sugar"). This explains why honey is sweeter than sugar. Sucrose is followed by glucose, maltose (disaccharide), and lactose (disaccharide). Anyone who has tasted rapeseed honey knows that it is not as sweet as other honey varieties. This is due to the predominance of glucose over fructose in its composition.
- maltose, turanose, isomaltose, sucrose, maltulose, isomaltulose, nigerose, trigalose, gentabiose, laminaribiose.
Sucrose in nectar honey reaches up to 1%-6%, and in honeydew honey – up to 10%.
Upon abundant forage, the percentage of sucrose might increase as a result of disturbed enzyme processing of nectar, or when forage is too close. Then nectar is retained in bees´ honey sacs for a shorter period of time.
In honey stored in normal conditions, the amount of sucrose gradually decreases due to its long enzymatic decomposition. The invertase enzyme remains active even after honey has been extracted from the combs and stored.
Regardless of the constant effect of invertase, the level of sucrose in honey can never reach 0.
The increased percentage of sucrose is a sign of poor quality and adulteration.
Maltose affects the speed of honey crystallization. If it reaches 6-9% in honey (acacia), the latter crystallizes slowly. If it is 2-3% (sunflower, rapeseed, sainfoin, etc.), crystallization is faster.
More complex sugars (containing more than 2 monosaccharides in their molecules):
Honey contains some oligosaccharides. There are no complex carbohydrates such as polisaccharides – fibers, for example.
The following higher sugars can be found in honey:
- erlose, panose, maltotriose, kestose, isomaltotriose, melizitose, isopanose, 6-α-3-isomaltose glucose, raffinose, isomalt tetroses, isomalt pentoses.
Honey contains dextrins which do not exceed 2% in nectar honey, and 5% in honeydew honey. In some varieties of honeydew honey they might reach 12%.
Some types of honey contain melicitose (upon hydrolysis, it yields two molecules of glucose and one molecule of fructose). The presence of melicitose is mostly typical of honeydew honey.
Water is second in quantity in the composition of honey. That is the residual moisture in honey after nectar ripening. The percentage content of water depends on the level of honey maturity, the weather and climatic conditions, the nature of nectar, and the conditions of honey storage after its extraction.
No single international norm for the water content in honey has been established. According to the Bulgarian State Standard, the permissible quantity of water in honey should be from 13,50 to 20%. In France, for example, the upper limit is 18%.
If the moisture content exceeds the abovementioned, a process of honey fermentation commences, since all varieties of honey contain a certain amount of yeasts (about 25 types have been established). They get into the nectar from the air, and thence bees bring them into the hive. If water content in honey is under 17%, honey will not ferment, no matter what the amount of yeasts is. At 17%-18% humidity, it will not fermentate either, if yeasts are less than 10 per 1 g. When water content is more than 20%, yeasts freely multiply, and at 25% humidity fermentation is fast. Yeast growth is also dependent on the amount of nitrogen (protein substances) and mineral salts. Therefore honeydew honey tends to ferment faster.
Honey is hygroscopic. Which means that it readily absorbs moisture from the air. It is recommended that honey should be stored in rooms with 60% relative humidity (no more than 80%).
Honey that has been prematurely extracted from the hive, before it’s ripe, contains more water. See how bees make honey. There are a number of ways to remove the excess moisture, but they are not the subject of this post.
Micro and Macro Elements
They constitute an insignificant portion in the overall composition of honey. Honey contains:
- phosphorus, iron, magnesium, manganese, calcium, chlorine, copper, sulfur, potassium, sodium and the like.
Depending on the nectar as a raw material, some types of honey might contain:
- aluminium, beryllium, boron, bismuth, barium, vanadium, germanium, gallium, gold, cobalt, lithium, molybdenum, nickel, lead, silver, silicon, strontium, titanium, chromium, zinc, zirconium.
The majority of authors believe that darker varieties of honey are richer in mineral (and nitrogen) substances. Lighter varieties contain 4 times less iron, 2 times less copper and 14 times less manganese.
Honey that is stored in metal containers (copper, iron, zinc) slowly dissolves metals and forms salts with them.
Mineral substances in honey help to detect its adulteration with sugar, whether it has been done directly or by feeding bees with sugar syrup. In such honey mineral substances are present in the form of traces, and silicon is the predominant element.
One of the unique characteristics that distinguishes honey from other sweeteners is the presence of enzymes in its composition. The following enzymes have been detected in honey:
- invertase, diastase (α-amylase, β-amylase), catalase, phosphatase, dehydratase, oxidase, peroxidase, reductase, maltase and lipase.
Invertase disintegrates sucrose into two simple sugars – fructose and glucose. Invertase is both of plant and animal origin – from nectar as a feedstock and from the bee glands.
Diastase (amylase) catalyses the breakdown of starch and other polysaccharides into maltose. However, complex carbohydrates, such as starch, are not present in honey. For the moment, it is not quite clear what the function of that enzyme is in honey. On the other hand, the amount of diastase is one of the major indicators for honey assessment in some European countries. Diastase, like invertase, is both of animal and plant origin.
Its presence is directly related to the other ferments in honey. The optimal lower limit of diastase number should be 8, if honey is to be considered good quality honey.
Diastase activity shows whether honey had been heated or kept under poor conditions. Heating, as well as long term storage, decompose this enzyme. Therefore there are certain requirements regarding the minimum values (lower limit) of diastase.
It is important to know that with some varieties of honey, such as acacia, lavender, etc.,the diastase number is lower in principle, which should not be interpreted as poor quality of honey.
Conversely, in spoilt honey the diastase quantity is increased in direct proportion to the degree of its decomposition. It would be wrong to consider such honey valuable, since the diastase increase results from the fermentation.
Phosphatase comes from the nectar and honeydew. It decomposes the organic compounds of phosphoric acid.
Katalase activates and accelerates biologic processes whereupon the transiently formed hydrogen peroxide is decomposed into water and oxygen.
Honey ferments remain active in human body. All honey enzymes might be destroyed or have their effect reduced upon excessive heating of honey.
Honey contains the following acids:
- gluconic, malic, lactic, oxalic, citric, tartaric, acetic, succinic, maleic, pyruvic, pyroglutamic, etc. They are mainly found in the form of salts.
They come from the nectar, honeydew and bee glands.
Aged honey, honey that has begun to spoil, or honey adulterated with invert sugar, has increased acidity.
Upon honey heating, part of fructose decomposes, forming levulinic and formic acids.
Formic acid is not usually found in honey, as has been considered so far, but only when it begins to spoil.
Honeydew honey has pH over 4, while the pH of nectar honey is under 4.
Proteins and Nitrogenous Substances
They can be found in small quantities. In nectar honey they vary from 0,1% to 0,3%, and in honeydew honey - from 0,3% to 0,5%. Their percentage is dependent on the amount of pollen and other organic substances added during honey collection.
They cannot be found in honey adulterated with sugar, or there are only traces of them.
In honey obtained at the extrusion of old honeycombs or such with maggots and pollen, there is an increased amount of proteins.
Proteins have partly plant origin, but most of them are of animal origin. They might come from the glandular secretion of bees, pollen and nectar.
Honey contains up to 17 amino acids. Not all varieties of honey contain the amino acids mentioned in their full range which depends mostly on the sources of nectar.
The following amino acids have been found in honey:
- lysine, histidine, arginine, asparagine, threonine, serine, glutamine, proline, glycine, alanine, cystine, valine, methionine, isoleucine, tyrosine, phenylalanine and β-alanine.
Honey contains the following vitamins:
B1 (aneurin) - up to 0.1 mg./kg., B2 (riboflavin) - up to 1.5 mg./kg., B3 (pantothenic acid) - up to 2 mg./kg., folic acid, B6 (pyridoxine) - up to 5 mg./kg., H (biotin), K (phylloquinone), C (ascorbic acid) – up to 30 - 50 mg./kg., E (tocopherol), carotene (provitamin A), vitamins PP (nicotinic acid) – up to 1 mg.
The quantity and type of vitamins depend on the nature of plants honey has been obtained from. Thus for example, vitamin C can be found in greatest amounts in mint honey.
- anti-bacterial, antifungal, hormonal, aromatic substances, substances with anti-diabetic properties, etc .;
- antioxidants - presented mainly by the group of the flavonoids, one of which is pinocembrin;
- biogenic stimulators;
- substances stimulating cell growth - branches of various trees that have been kept in water solution and then planted, grow much faster.
- ethereal and aromatic substances;
- coloring agents such as carotene, flavones, derivatives of chlorophyll, melanin;
How to choose honey according to the label description, if we buy it from the store?
FOR EXAMPLE, such a label could read: water – no more than 21%, sucrose – no more than 6%, glucose and fructose – no less than 82%, diastase number – no less than 7, total acidity– no less than 4%.
The exact percentage of other substances cannot be precisely indicated, since it depends on the variety, the place of collection, etc.