Spray-Drying Microencapsulation of Natural Bioactives: Advances in Sustainable Wall Materials

Background/Objectives: In recent years, increasing attention has been paid to the stabilization of natural biologically active compounds in order to expand their application in the food, pharmaceutical, and cosmetic industries. Such compounds, such as polyphenols, essential fatty acids, or vitamins, are extremely sensitive to environmental factors. This study aims to review the spray-drying-based microencapsulation technology and its application for stabilizing sensitive biologically active substances. Methods: This article systematically analyzes the main steps of the spray-drying microencapsulation process and discusses traditional and innovative wall materials, including natural polymers (polysaccharides and proteins), as well as new raw material sources (e.g., yeast cells, canola and pea protein isolates, and hemicelluloses). It also examines the potential of these systems for the stimulated release of active ingredients. Results: This review provides a comprehensive overview of the main stages of the spray-drying process and critically examines both conventional (e.g., maltodextrin and gum Arabic) and innovative wall materials (e.g., plant-based proteins and food industry by-products). Studies show that using different wall materials can achieve high encapsulation efficiency, improve the stability of biologically active substances, and control their release. Various compounds have been successfully microencapsulated—polyphenols, essential oils, carotenoids, fatty acids, and vitamins—protecting them from oxidation, light, and temperature. The review identifies key factors that can enhance product quality, increase encapsulation yield, and reduce processing costs and energy input—offering meaningful insights for optimizing the microencapsulation process. Conclusions: Spray-drying-based microencapsulation is an advanced technology that effectively protects sensitive active ingredients and allows for wider industrial food, pharmaceutical, and cosmetic applications. In the future, more attention is expected to be paid to personalized formulations, stimulated release systems, and sustainable wall materials from by-products.