Encapsulation and in vitro evaluation of phenolic compounds of propolis by spray and freeze drying

Freeze and spray drying techniques were evaluated for propolis encapsulation to suppress the bitter taste of propolis. Effects of coating materials and stabilizers on phenolic compounds, antioxidant activity, and release of phenolic compounds from encapsulated propolis powder during in vitro digestion were remarkable. Among the proteins, sodium caseinate was less effective for encapsulating bioactive compounds while maltodextrin was the most suitable carbohydrate-based carrier. The propolis powders encapsulated by maltodextrin and whey protein had the highest retention of phenolic compounds and antioxidant activity. Polyglycerol polyricinoleate as stabilizers presented better results on phenolic compounds and antioxidant activity compared to Tween 20. During model in vitro digestion, the release of phenolic compounds was restricted in the oral phase. The higher releases in the stomach and intestinal phases were observed as intended. Spray and freeze-drying encapsulation resulted in propolis powder presenting similar properties and appropriate as a functional ingredient in the food industry. Novelty impact statement Several methods can be used for the encapsulation of propolis, but the functionality of obtained propolis powder is important and besides that, the bitter taste of propolis can be suppressed by minimizing the release of phenolic compounds in oral digestion. In line with these targets, the functional properties of propolis powder obtained by spray and freeze drying in relation to coating materials and stabilizers were investigated. Spray drying and freeze-drying processing resulted in propolis powder presenting a functional ingredient in the food industry.