Physicochemical and bioactive characterization of pink guava pulp microcapsules prepared by freeze-drying using coffee mucilage as a wall material
María Carolina Otálora, Andrea Wilches‐Torres, Jovanny A. Gómez Castaño
Abstract
This study investigated the potential of coffee mucilage (CM), a readily available coffee industry byproduct, as a wall material for the microencapsulation of pink guava pulp via freeze-drying (FD). Microcapsules with varying wall compositions incorporating powdered coffee mucilage, maltodextrin (MD), or a combination of both (FD-CM/MD) were developed and characterized using techniques such as FT-IR spectroscopy, SEM, TGA/DSC, and zeta potential analysis. The retention of bioactive compounds was assessed using total phenolic content, antioxidant capacity and carotenoid analyses. Results revealed that the incorporation of powdered coffee mucilage significantly influenced the physicochemical properties of the microcapsules, resulting in larger particle sizes and less rough surface morphologies compared with maltodextrin-based formulations. Notably, FD-CM microcapsules exhibited a thermal stability (Tg ≈ 50 °C) and retention total polyphenols of 30.19 ± 5.26 mg GAE/g dry weight (DW) and carotenoids of 5.50 ± 0.29 mg β-carotene/100 g DW, which can be attributed to the protective effects and inherent antioxidant capacity of 91.85 ± 9.93 μmol Trolox Equivalents/g DW in the coffee mucilage matrix. While influencing the color attributes, all microcapsule formulations retained a commercially appealing (h ab = 79.80 ± 0.06) red-yellow hue. This study demonstrated the potential of powdered coffee mucilage as a sustainable and effective encapsulating wall material for enhancing the stability and bioavailability of bioactive compounds in food products. • Coffee Mucilage Emerges as a Novel Wall Material for Microencapsulation. • Microencapsulation with Coffee Mucilage Significantly Enhances Bioactive Retention of Guava Carotenoids. • Coffee Mucilage Incorporation Improves Physicochemical Properties of Microcapsules. • This Study Promotes Sustainable Valorization of Coffee Wasted By-products. • Microencapsulated Pink Guava Pulp Shows Potential for Functional Food Applications.