Fresh, recently deposited in the hive, propolis may have a greenish, gray, brown, greenish-brown color. Over time, it darkens and sometimes becomes even black. At room temperature, propolis becomes viscous, at temperature + 15° C it hardens. Freezing (0° C and below) makes propolis brittle, it crumbles easily. The degree of hardness of propolis indicates its quality. High-quality propolis at room temperature becomes slightly elastic, but when you press it with a nail it leaves no trace.
Depending on where in the hive the propolis was collected it is divided into “soft” and “hard”. The “soft” propolis is considered to be of higher quality. It contains few impurities, especially wax. The beekeeper collects it between frames and on frames. The “hard” propolis, collected from the entrance and the bottom of the hive, contains more impurities and wax.
At room temperature, propolis becomes viscous, at temperature + 15° C it hardens. Freezing (0° C and below) makes propolis brittle, it crumbles easily. The degree of hardness of propolis indicates its quality. High-quality propolis at room temperature becomes slightly elastic, but when you press it with a nail it leaves no trace. Depending on where in the hive the propolis was collected it is divided into “soft” and “hard”. The “soft” propolis is considered to be of higher quality. It contains few impurities, especially wax. The beekeeper collects it between frames and on frames. The “hard” propolis, collected from the entrance and the bottom of the hive, contains more impurities and wax. Propolis melts at a temperature of 80-104 ° C, while the wax melts at 62-72 ° C. This temperature difference is used to clean the propolis from excess wax.
The smell of fresh propolis is fragrant, harsh and reminiscent of the smell of poplar and birch buds, honey, wax and vanilla. The taste of propolis is bitter. After prolonged chewing there is a slight burning sensation in the mouth. The density of propolis is 1.11-1.18 g/cm3, which is slightly heavier than water. When the content of wax is high, the propolis does not sink in water. It easily dissolves in petroleum, ether, alcohol, gasoline, chloroform, turpentine, acetone, vegetable and animal fats, ammonia, and acetic acid. In water, propolis is almost insoluble. Its water-soluble fraction is 1-3%.
The chemical composition of propolis is very complex. It includes cinnamon alcohol, vanillin, acacetin, quercetin, galangin, caffeic acid and chrysene (a natural dye) which gives honey, wax and propolis a specific color. In propolis, there are 8 amino acids, 5 of which are essential, trace elements – aluminum, boron, K, Ca, Mg, Cu, and Zn. The most studied propolis substances are flavonoids, frolic and benzoic acids, cinnamic acid and aromatic aldehydes. Flavonoids (flavones, flavonols), phenolcarboxylic acids, oxy-coumarin, furol and benzoic acids have the highest pharmacological, antiviral, and antiparasitic activity. They act as anti-inflammatories, stabilize lysosomal membranes and have a beneficial effect on the capillary wall, on the circulatory system and on the tone of the blood vessels. Flavonoids produce a diuretic and choleretic effect, as they have the properties of estrogen and stimulate the endocrine glands (thymus, thyroid, pancreas, adrenal glands).