Mechanistic insights into biopolymer-based encapsulation of black cardamom (Amomum subulatum) oleoresin via spray drying: Techno-functional, physicochemical properties, and release of bioactives in simulated gastrointestinal and milk matrix

Abstract

Black cardamom is an underutilized spice valued for its distinct aroma and flavour in food, but its commercial potential as a functional ingredient in the concentrated form of oleoresin is limited due to its volatility and oxidative degradation. This study aimed to extract BCO using supercritical fluid, followed by encapsulation via spray drying with different biopolymers such as gum arabic (GA), maltodextrin (MD), whey protein (WP), and their combination to enhance its stability and functionality. The resulting encapsulates were evaluated for yield, moisture, solubility, thermal, structural, and functional characteristics. Among the carriers, GA based encapsulates exhibited the highest encapsulation efficiency and superior functional attributes such as solubility, wettability, bulk density, and tapped density. FTIR and XRD analyses confirmed strong intermolecular interactions and successful amorphous matrix formation. SEM revealed spherical, smooth microcapsules while thermal analysis (DSC and TGA) indicated better thermal stability, confirming the effectiveness of GA as a carrier. Furthermore, in-vitro release studies under simulated gastrointestinal conditions revealed that GA formulations released over 80 % of the bioactive compounds, indicating strong potential for targeted delivery. In addition, the controlled release behavior of 1,8-cineole and α-terpinyl acetate in milk revealed that GA presented the highest and most sustained release profiles, reaching over 95 % for 1,8-cineole and over 85 % for α-terpinyl acetate within 210 min, demonstrating the efficacy of the carriers in delivering bioactives in functional food matrices. These results highlight the importance of selecting biopolymers for the development of stable, functional ingredients with controlled release that are suitable for food and pharmaceutical applications.