Basic honey analysis

At the accredited Chemical Laboratory of Lamia, honey analysis includes, among other things, the following:

Glucose and Fructose Control in Honey

• Glucose is a simple monosaccharide found in plants. It is one of the three dietary monosaccharides, along with fructose and galactose, that are directly absorbed into the bloodstream during digestion. It is the most important carbohydrate in biology, as cells use it as the primary source of energy and as a metabolic intermediate. Glucose is one of the main products of photosynthesis and is used as fuel for cellular respiration. Glucose exists in many different molecular structures, but all these structures can be divided into two families of stereoisomers. Only one pair of isomers from these exists in nature, that derived from the "dextrorotatory form" of glucose, denoted as D-glucose. D-glucose is sometimes referred to as dextrose. The term dextrose comes from "dextrorotatory" glucose. The name is therefore confusing since the enantiomer rotates light in the opposite direction. Starch and cellulose are polymers derived from the dehydration of D-glucose. The other stereoisomer, called L-glucose, is rarely found in nature. The name "glucose" comes from the Greek word "γλυκύς" (glykýs), meaning "sweet". The suffix "-ose" denotes a sugar.


• Fructose, or fruit sugar or levulose, is an organic compound belonging to the group of carbohydrates also known as monosaccharides. It is a natural sugar found in fruits. keto-enol-aldo or ketone-enol-aldone tautomerism. Fructose is considered the sweetest monosaccharide found free in nature and most often accompanies glucose in grapes and other fruits, hence the name fruit sugar. It is also found in various vegetables as well as in syrups. Fructose, along with glucose, are the components of the disaccharide sucrose, common table sugar, as well as polysaccharides, such as inulin.

Sucrose Content Control

• Sugar (scientific name sucrose) is the common name for sweet and water-soluble carbohydrates, many of which are used in food. There are various types of sugars produced from different sources. The simple variations are called monosaccharides, with examples of this group being glucose, fructose, and galactose. Common processed white sugar is sucrose, which is a type of disaccharide, and maltose and lactose also belong to the same group. Larger chemical compounds of sugars are called oligosaccharides. There are also chemically different compounds that taste similar to sugar but are not classified as sugars, such as stevia and xylitol, and are used for dietary purposes or by people with diabetes. From a chemical point of view, white sugar is a chemical compound of one molecule of glucose and one molecule of fructose as a product of photosynthesis of plant cells. Its molecular chemical formula is C12H22O11, and in its pure form it is white and colorless. When heated above 200 °C, it turns into a sticky mass with a brown color and a bitter taste, called caramel. Like all polysaccharides, it is hydrolyzed in solutions of acids or bases and by specific enzymes, whereby it is separated into the polysaccharides that constitute it. Sweets generally contain sugar.
  
  The natural juice collected by bees is mainly sucrose, and with the catalytic action of the invertase of the hypopharyngeal glands of the foraging bees, it is broken down into glucose and fructose. Depending on the botanical origin of the honey, its fructose and glucose content is affected, and there are honeys with a high monosaccharide content (sunflower, heather) and honeys with a low monosaccharide content (fir honey, pine honey). However, the botanical origin also affects the sucrose concentration, but this parameter is also affected by the enrichment of honey with invertase. This increases with the feeding of bees with sugar syrup, and sucrose increases. Acceptable values: blossom honeys should have a sum of fructose and glucose greater than 60%, and honeydew honeys with their mixtures greater than 45%. Limited values must also be maintained for honeys in sucrose less than 5%, with the exception of acacia and citrus honeys, eucalyptus which is allowed to have up to 10%, while lavender up to 15%.

Total Acidity Measurement

• Often also called Total Acidity, although a more correct term is titratable acidity. Titratable acidity measures the total available hydrogen ions that can react with sodium hydroxide. Although acidity is considered a simple parameter, it is essentially a reflection of the complex interactions of hydrogen ions, organic acids, organic salts, and cations in honey.

Conductivity Measurement

• Conductivity is one of the characteristic properties of matter by which the ease or difficulty of the propagation of various forms of energy within it is determined. Conductivity is therefore related to the resistance that matter presents to the flow of energy, which also depends on the losses that may be observed due to the conversion of the initial energy into other forms of energy within the same material. For this reason, the study of the structure and properties of materials is considered necessary. Honeys with high conductivity are e.g., fir, oak, chestnut. Low conductivity is found in orange blossom, acacia, and thyme honey. The conductometric determination is carried out with acceptable values provided by law. However, the conductivity limits vary depending on the botanical origin of the honey. Chestnut honeydews as well as their mixtures should show a conductivity greater than 0.8mS/cm, while in the rest this parameter should be lower. Therefore, a honey labeled as blossom honey should have a conductivity of less than 0.8mS/cm, while a honeydew honey or a mixture thereof with blossom honey should have a conductivity higher than 0.8mS/cm.  

Moisture Calculation

• As is known, atmospheric air also contains water vapor originating from the evaporation of liquid surfaces, mainly the seas. The presence of this water vapor in the air is called humidity. Atmospheric humidity is divided into "absolute" and "relative humidity". Absolute humidity is the mass of water vapor (in grams, gr) contained in 1 m³. From the definition, we understand that it is the water vapor content of the air. Relative humidity is the ratio of the amount or mass of water vapor contained in the air to the amount or weight of water vapor it can contain (under the same temperature and pressure) until it is saturated. Relative humidity is expressed as a percentage.

Chemical determination of Hydroxymethylfurfural

• Hydroxymethylfurfural (HMF) is a compound resulting from the breakdown of simple sugars (such as glucose or fructose) at a pH less than 5 and increases rapidly with the heat treatment of honey. Thus, the HMF content can be an indicator of the heating time and storage of honey at high temperatures. It is a furan derivative formed from sugars, and in particular from hexoses, under heating or acidic conditions, while the rate of its formation is also affected by the presence of metal elements and nitrogenous compounds that act catalytically. Increased breakdown of HMF leads to the formation of dark-colored compounds called melanoidins, known during prolonged heating of honey, its color becomes darker. Good quality honey contains a small amount of HMF. Although not dangerous to human health, there is a legal regulation for its levels in honey (EU: ≤40mg/kg for honeys other than bakers honey).

Calculation of diastase number (or amylase)

• It is an enzyme that breaks down starch and exists in 3 forms: α-amylase: in the presence of calcium, it acts on various points of starch and gives amylphein, maltotriose, and maltose, while from amylopectin, maltose, glucose, and dextrins.
  β-amylase: Acts on the non-reducing ends of starch giving maltose and
  γ-amylase: whose action yields glucose.
  Amylase is produced by both plant and animal organisms.
  The breakdown as an enzyme is affected by the action of high temperatures, and therefore a heated honey shows reduced values of the activity of this enzyme. But this also depends on the botanical origin of the honey.
  But also in the legislation for honey, there are lower diastase values for some marginal categories of honey.
  A high rate of sap collection that affects bees, as well as a large amount of available food that does not allow enrichment with enzymes, as in cases of feeding, leads to a reduction in the enzymes action, but the enzymatic action of breakdown is also reduced by the duration of storage.

Determination of water-insolubles

• Generally: Not more than 0.1 g/100g  Pressed honey: Not more than 0.5 g/100