Propolis
Introduction
Extracts NZ Ltd
Processing
Alaron Products Ltd
Production
Comvita NZ Ltd

Download a PDF of the 'Propolis' Technologists Practice Case Study.



Published: 2005

Propolis

Processing the propolis

propolis extract

Propolis extract (liquid) packed for transport

extract equipment

General view of extraction equipment

film evaporator process

Ian checking the falling film evaporator process

Raw propolis is the bee's building material and arrives at the plant along with other material such as wax and dead bees. The extraction process is the same for all propolis. High strength, food grade ethyl alcohol is the most efficient and the safest solvent as it helps kill harmful bacteria and at the same time it carries out the extraction. It should be noted that propolis itself has strong antimicrobial properties. The raw propolis is placed into stainless steel cylinders. Passive extraction occurs through the immersion of the raw propolis in the alcohol, allowing the pure material to dissolve in the solvent alcohol. The residue remaining is waste, which contains beeswax and other unwanted materials.

The propolis dissolves in the alcohol to form a tincture – a propolis solution in alcohol. A counter current process is used to move the liquid propolis through five stages using similar stainless steel cylinders each containing raw propolis. In this way the strength of the propolis solution is progressively increased and the efficiency of the extraction is improved. Any particulate matter (suspended and undissolved particles) is removed by passing the liquid through several stages of filtration until it all passes through a final polishing filter.

Samples of the liquid are sent to Christine for testing. The testing determines the levels of concentration, which may be a high as 45%. At this stage the liquid is a non-standard product. The product is usually supplied to customers in strengths that vary between 5% and 40% pure propolis.

When an alcohol free product is required Mono Propylene Glycol (MPG) is introduced and the alcohol removed so as to produce an alcohol-free liquid product in which the propolis is sold. MPG also has the advantage that it produces a more water-soluble product than alcohol. Propolis is also produced as a bulk dry powdered product, ready for encapsulating by evaporating off the liquid solvent and drying it.

The product passes through three more stages to produce the powder:

  1. It is made into propolis paste by evaporating off the liquid. This paste is virtually pure propolis.
  2. The paste is placed in the freeze dryer, which causes further evaporation and produces a dry, crusty powder.
  3. Free flow agents are blended with the pure propolis and the product is milled to a very fine powder.

Propolis powder is packed in airtight double foil pouches to protect the product from the light, ready for palletising and transport to Alaron Products.

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