Use of propolis powder as a functional food ingredient

IRIGOITI Y.; YAMUL D.K.; NAVARRO A.S.

Ankara

Congreso; International Congress on Bee Sciences; 2022

Ulas Acaroz

Propolis contains numerous compounds with antioxidant and pharmacological activities that make it the ideal candidate to be used as a functional ingredient in foods. However, its solubility in alcohol and its strong and unpleasant taste limit its use as a food ingredient. The objective of the work was to encapsulate a propolis ethanolic extract by co-crystallization in a sucrose matrix to obtain an easily-handled alcohol-free powder to be used as a food ingredient. The effect of the propolis extract on colour, moisture content, solubility, particle size distribution, flow properties and spectroscopic characteristics (FTIR) of the co-crystallized powders (10-40% w/v extract) was determined. Polyphenols and flavonoids content and antioxidant capacity (ABTS and DPPH) during storage of the powders were also analysed. The powder was incorporated in a chocolate flavoured pre-mixed powdered dessert and the colour properties were assessed. The propolis co-crystallized powders showed moisture contents below 2% and solubility values higher than 95%. The dynamic angle of repose and Hausner ratio were between 41º-48º and 1.05-1.19, respectively, in samples with up to 30% w/v extract indicating a good flowability of the powders. The increase in the propolis content decreased the luminosity and made the powder more red-yellowish. The content of propolis influenced the particle size of the co-crystallized powders. As propolis content increased, the particle size distribution shifted to higher sizes. Thus, at low concentrations, the matrix structure was determined by the sucrose agglomerate, but as the volume of propolis extract increased, the encapsulated compound also had an impact. The FTIR results showed that the presence of propolis did not alter the crystalline sucrose structure. Entrapment yields higher than 84% (flavonoids) and 78% (polyphenols) were obtained. During storage of the powders, high stability of these compounds was observed under light, darkness and refrigeration conditions. The addition of the powder to the chocolate dessert did not change the luminosity but slightly decreased a* and b* colour coordinates. Thus, the co-crystallization technique becomes a low-cost alternative for the protection of bioactive compounds of propolis and to obtain a powder with suitable technological properties and high antioxidant activity to be used as a food ingredient.