Food and Bioproducts Processing 1 1 6 ( 2 0 1 9 ) 196–211 Contents lists available at ScienceDirect Food and Bioproducts Processing journal homepage: www.elsevier.com/locate/fbp Encapsulation of non-dewaxed propolis by freeze-drying and spray-drying using gum Arabic, maltodextrin and inulin as coating materials Luka ˇ Sturm a , Ilja Gasan Osojnik ˇ Crnivec a , Katja Isteniˇ c a , Ajda Ota a , Polona Megu ˇ sar a , Anˇ ze Slukan a , Miha Humar b , Steva Levic c , Viktor Nedovi´ c c , Rok Kopinˇ c d , Matja ˇ z Deˇ zelak d , Adriana Pereyra Gonzales d , Nata ˇ sa Poklar Ulrih a,∗ a Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia b Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia c Department of Chemical Engineering, Faculty of Technology and Metallurgy, University of Belgrade, Kamegijeva 4, 11000 Belgrade, Serbia d Medex d.o.o., Linhartova cesta, 49 A, 1000 Ljubljana, Slovenia a r t i c l e i n f o Article history: Received 1 March 2019 Received in revised form 16 April 2019 Accepted 29 May 2019 Available online 4 June 2019 Keywords: Encapsulation Propolis Gum Arabic Spray-drying Freeze-drying Fish oil a b s t r a c t The aim was to obtain alcohol-free, water-dispersible propolis powder from non-dewaxed propolis extract, with high levels of phenols, with either freeze-drying or spray-drying. Optimisation was performed with different wall materials, centrifugation settings and propolis:carrier ratios, and was carried out by monitoring the effect of one parameter at a time on the dependable variables. The powders obtained contained high phenol lev- els, which included known bioactive components, and also showed high dispersibility in cold water and high antioxidant activity. Furthermore, the propolis powders were stable in water for up to 24 h, and the release of encapsulated phenols did not change across different environmental values, as pH 3–6. Differential scanning calorimetry showed that propolis interacts with and stabilises the carrier material (gum Arabic), also high pressure liquid chromatography showed that the profiles of the powders remained unchanged across all encapsulation techniques. This study demonstrates that the same propolis formula- tions can be fine-tuned to suit specific final applications and confirms that freeze-drying is a viable alternative to the more established spray-drying for encapsulation of propolis. This study also demonstrates that non-dewaxed propolis extract is a better alternative for encapsulation purposes, as no phenolic compounds are lost during its processing. © 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. 1. Introduction Propolis is a resinous substance that is collected by honeybees from various plant sources. It has been classified into seven different types, ∗ Corresponding author. E-mail address: natasa.poklar@bf.uni-lj.si (N. Poklar Ulrih). poplar type being the most widely spread. Its composition varies, although generally it is composed of 50% resin, 30% waxes, 10% essen- tial and aromatic oils, 5% pollens and 5% other organic and inorganic substances (Burdock, 1998; Gardana et al., 2007; Huang et al., 2014; Zhang et al., 2016). Over 500 compounds have been identified in propo- lis samples, including phenolic acids, flavonoids and terpenes (Gardana et al., 2007; Huang et al., 2014), to which biological activities of propo- lis have mainly been attributed to (Banskota et al., 2001; Castro, 2001; Huang et al., 2014). As propolis is reputed to have antiseptic, antimicro- https://doi.org/10.1016/j.fbp.2019.05.008 0960-3085/© 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.