Main methods of honey adulteration and techniques for their detection

Honey adulteration is defined as the addition of various impurities to bee honey or the substitution of natural honey with other products similar to it. Most often, in uncontrolled sales, artificial honey and invert (a solution of invert sugar, prepared from honey, sugar, and water (7.5 kg of honey, 75 kg of sugar, and 21 L of water); this mixture is kept for 5-10 days at a temperature of 34-36°C) are passed off as natural honey. Impurities added to natural honey to increase its weight include sucrose, starch, chalk, molasses, industrial glucose, flour, gelatin, etc.

Sometimes such honey can be identified immediately by its taste and smell, but more often only through laboratory chemical analysis.

Determination of sucrose impurity. When honey is adulterated with sucrose, organoleptic properties deteriorate, diastase activity, mineral content, and invert sugar content decrease, while sugar content increases. The adulterated product shows dextrorotation. Consequently, to detect this type of adulteration, it is necessary to determine organoleptic indicators, diastase activity, ash content, cane and invert sugar content, and optical activity.

Determination of sugar "honey". Sugar (supplementary, express) "honey" is obtained as a result of feeding bees with sugar syrup. Such "honey" is an adulterant.

Freshly extracted sugar "honey" has a liquid consistency, light color, faint aroma, and lacks the astringency characteristic of natural honey.

Chemical indicators for sugar "honey" are as follows: total acidity not more than one normal degree, ash content below 0.1%, cane sugar content above 5%, and the adulterant shows dextrorotation.

Determination of honey heating. Honey is heated for decrystallization, to stop fermentation, and during adulteration. This impairs organoleptic indicators (honey darkens, aroma weakens, a caramel aftertaste appears), reduces enzymatic activity and bactericidal properties, and increases the hydroxymethylfurfural content. Based on the above, to determine honey spoilage by heating, one should determine organoleptic indicators, enzymatic activity, hydroxymethylfurfural content, and foreign impurities.

Determination of honey fermentation. This type of spoilage is a consequence of storing honey with a water content above 21%. Honey possesses pronounced hygroscopicity, therefore storing it in non-airtight containers under conditions of high ambient humidity leads to an increase in the water content in the honey. Osmophilic yeasts become activated, and the honey begins to ferment.

At the beginning of fermentation, an intensification of the aroma is noted, then a sour smell appears (which intensifies when the honey is heated). The honey swells, foam appears on the surface, and gas bubbles appear in the honey mass. Microscopic examination of such honey reveals the fermentation agents — yeast.

Determination of beet (sugar) molasses impurity. The addition of beet molasses to honey impairs its organoleptic properties, reduces the invert sugar content and diastase activity. The mixture has dextrorotation.

Qualitative reaction: to 5 ml of an aqueous solution of honey prepared in a 1:2 ratio, add 5—10 drops of 5% silver nitrate. Turbidity of the mixture and the appearance of a white precipitate indicate the presence of beet molasses in the honey.

Determination of starch molasses impurity. Changes in honey upon the addition of starch molasses are similar to the changes mentioned above.

Determination of honey adulteration by the addition of molasses

Qualitative reaction: to 5 ml of a filtered aqueous solution of honey prepared in a 1:2 ratio, add dropwise a 10% barium chloride solution. Turbidity and the formation of a white precipitate after adding the first drops of the reagent indicate the presence of starch molasses in the honey.

Methods for detecting starch, flour, and gelatin impurities

Determination of starch and flour impurity. Changes in honey upon the addition of starch and flour are similar to the changes of sugar molasses.

Qualitative reaction: 5 ml of an aqueous solution of honey in a 1:2 ratio is heated in a test tube to a boil, cooled to room temperature, and 3—5 drops of iodine solution are added. The appearance of a blue color indicates the presence of starch or flour in the honey.

Determination of gelatin impurity. Gelatin is added to honey to increase viscosity. This impairs the taste and aroma, reduces enzymatic activity and invert sugar content, and increases protein content.

Qualitative reaction for the presence of gelatin:

• To 5 ml of an aqueous solution of honey in a 1:2 ratio, add 5—10 drops of 5% tannin solution.
• The formation of white flakes indicates the presence of gelatin in the honey.
• The appearance of slight turbidity is evaluated as a negative reaction for gelatin.

Determination of honeydew honey impurities

Determination of honeydew honey. Lime reaction: in a test tube, one volumetric part of an aqueous solution of honey in a 1:1 ratio is mixed with two volumetric parts of limewater and heated to a boil. In the presence of honeydew honey, brown flakes are formed, which precipitate.

To prepare limewater, follow this sequence of actions:

1. Take one part of quicklime and one part of water.
2. Let the solution stand for 12 hours (stirring 2—3 times during this time).
3. Decant the top clear layer of liquid and use it for the reaction.