Freeze-dried microencapsulation of bergamot pomace extract: stability and antioxidant performance in hydrophilic and lipophilic systems

Abstract

The use of microencapsulated antioxidant compounds is gaining increasing interest in both scientific and industrial fields due to their functional properties. In this study, a freeze-drying technique was applied to encapsulate an antioxidant extract obtained from bergamot pomace, a by-product resulting from the processing of this citrus fruit. Maltodextrin was used as a coating agent at a concentration of 20%. The resulting microencapsulated extract was then used to enrich two different matrices: (a) apple juice and (b) sunflower oil, in order to evaluate its effectiveness as a natural antioxidant. The antioxidant extract, the microencapsulated powder, and the enriched products were assessed for their physicochemical properties and antioxidant activity. In addition, the main characteristics of the enriched products were monitored during storage at 25 °C for 90 days. The freeze-drying process enabled the stabilization of the antioxidant compounds, facilitating their incorporation into both hydrophilic and lipophilic systems. The incorporation of the microencapsulated extract led to an increased content of polyphenols and enhanced antioxidant properties in both matrices, with these improvements maintained throughout the 90-day storage period.