Apple (Malus domestica) is one of the most widely consumed fruits globally owing to its nutritional value, sensory characteristics and health-promoting bioactive compounds. However, its high moisture content and active metabolic processes make it highly susceptible to microbial spoilage, enzymatic browning and quality deterioration during storage and distribution. Drying is an effective preservation technique that extends shelf life by reducing moisture content and water activity, thereby inhibiting microbial growth and slowing biochemical reactions. In recent years, advanced drying technologies such as microwave drying, vacuum drying and vacuum-microwave drying have gained considerable attention as alternatives to conventional hot-air drying due to their superior drying efficiency and product quality retention. This review critically examines the principles, drying mechanisms, process kinetics and quality characteristics associated with microwave and vacuum-based drying methods for apple preservation. Microwave drying utilizes volumetric heating to accelerate moisture removal, resulting in significantly reduced drying times and improved energy efficiency. Vacuum drying operates under reduced pressure, enabling moisture evaporation at lower temperatures and minimizing thermal degradation of heat-sensitive components.

The Vacuum-microwave drying combines the advantages of both technologies by enhancing drying rates while preserving color, texture, nutritional compounds and antioxidant activity. Comparative analysis of published studies indicates that vacuum-microwave drying generally provides the best balance between drying efficiency and product quality, producing dried apple products with superior rehydration capacity, reduced oxidation and enhanced storage stability. The review further discusses the influence of process parameters, including microwave power, vacuum level, drying temperature and pretreatment methods, on product quality and shelf-life performance. Current challenges related to equipment cost, process optimization and industrial-scale implementation are also highlighted. Overall, microwave and vacuum-based drying technologies represent promising approaches for the production of high-quality dried apple products with extended shelf life, improved nutritional retention and enhanced commercial value. Future research should focus on hybrid drying strategies, intelligent process control and comprehensive storage studies to support large-scale industrial adoption.