Freeze-drying, also known as lyophilization, is a state-of-the-art method for preserving food, offering excellent retention properties for nutrients, structure, and taste compared to other drying processes. Freeze-drying yields a product visually similar to fresh produce. However, due to the high energy requirements and operational costs associated with the process, its broader use as an industrial tool is limited. This review encompasses the optimization of all key stages, including pretreatment, freezing, primary drying, secondary drying, and storage. Process efficiency and product quality depend on a variety of factors, including raw material composition, pretreatment strategies (e.g., Pulsed Electric Fields), chamber pressure, shelf temperature, and freezing rate. These parameters are critical control points for determining the final product outcome. Optimizing these parameters is essential; as summarized by recent research, lyophilization effectively protects bioactive compounds, color, flavor, and rehydration ability in various food systems, including fruits, vegetables, meats, seafood, and specialty products. To achieve broader industrial adoption, this gold-standard method requires advancements in process intensification and hybrid drying systems, potentially integrated with intelligent process control. These advances are crucial to enhancing the economic viability of freeze-dried products and maintaining their reputation as the gold standard in creating high-quality, shelf-stable food products. This review consolidates current knowledge into a coherent conceptual model. The model clarifies the deterministic sequence by which adjustable processing conditions direct essential physicochemical changes within the food matrix, thereby defining the product ultimate nutritional, sensory, and stability properties. Establishing this cause-and-effect framework provides a foundation for systematic process improvement and facilitates broader commercial implementation.
Uwineza et al. (Mon,) studied this question.