Microencapsulation of Elaeis guineensis leaf extract powder enriched with bioflavonoid preserves its antioxidant and anti-inflammatory properties: spray drying optimization and powder characterization

Abstract

The oil palm tree (Elaeis guineensis) is potentially being exploited in the pharmaceutical and nutraceutical industries due to the significant bioactive potential of its leaf bioflavonoids. However, these phytocompounds are prone to degradation when exposed to excessive heat, light, and oxygen, making it essential to implement a protective mechanism for their stabilization. This research aimed to optimize the conditions for microencapsulation of oil palm leaf extract (OPLE) using spray drying technology. A single-factor experimental design was used to examine important parameters such as extract-to-wall material ratio, pH value, inlet air temperature and feed flow rate. Natural polymers such as gum Arabic (GA), maltodextrin (MD), modified starch (MS), β-cyclodextrin (BCD), and their combinations were used as encapsulating agents. The novelty of the study lies in the successful optimization of spray drying conditions that yielded high retention of bioactive compounds. Specifically, OPLE microcapsules prepared with maltodextrin at a feed flow rate of 30%, an inlet air temperature of 180 °C, an extract-to-wall material ratio of 30:70, and a pH of 7 retained 77.18% of total flavonoid content, 81.52% of total phenolic content, and demonstrated 82.22% DPPH radical inhibition. These optimized microcapsules exhibited desirable properties, including satisfactory bulk density, low moisture content, high solubility, and low hygroscopicity. Furthermore, the microcapsules demonstrated no cytotoxicity on Hs27 human skin fibroblast cell lines at a concentration of 10 mg/mL and revealed promising anti-inflammatory activity, surpassing the efficacy of a commercially available drug. These findings provide a novel foundation for the development of high-value active ingredients for nutraceuticals, with significant potential for industrial applications.