Using a technique called complex coacervation, scientists from Brazil’s São Paulo University report that it may be possible to obtain propolis in the “form of powder, alcohol-free, stable, with antioxidant property, antimicrobial activity against Staphylococcus aureus and with the possibility of controlled release in foods”.
Propolis is currently marketed for its health benefits. It is reported that propolis contains about 180 different compounds and the waxy resin has previously been linked to improvements of general health, skin health, and oral health.
In 2007, Argentine researchers reported that propolis may also be used as a natural food preservative, after tests showed that the ethanolic extract of propolis may inhibit E. coli development in vitro (Food Chemistry, doi: 10.1016/j.foodchem.2007.01.011).
According to the new study – published in LWT - Food Science and Technology – the current application of propolis is limited, however, because it is “alcohol-soluble and has strong flavour”.
The researchers describe microencapsulation by coacervation as being achievable by phase separation of one or many hydrocolloids and the subsequent deposition of the newly formed coacervate phase around the active ingredient (propolis), which is then suspended or emulsified in the same reaction media.
The encapsulation technique was examined for a range of conditions, including different pHs and concentrations of the encapsulants and core. The hydrocolloids used in this study were isolated soy protein (Supro 500E, Solae) and pectin (Genu type 8002, CPKelco).
Results showed that at pH 4.0 it was “possible to encapsulate propolis extract by complex coacervation”.
Importantly, the researchers noted that the process preserved the phenolic and flavonoids compounds present in free propolis.
“Furthermore, the encapsulation process preserved the antioxidant activity of the material, as well as its inhibitory activity to Staphylococcus aureus.
“These results improve the possibility of using propolis as a natural food additive,” they concluded.
Source: LWT - Food Science and Technology
Published online ahead of print, doi:10.1016/j.lwt.2010.09.010
“Microencapsulation of propolis extract by complex coacervation”
Authors: M. Pozippe Nori, C.S. Favaro-Trindade, S. Matias de Alencar, M. Thomazini, J.C. de Camargo Balieiro, C.J. Contreras Castillo