Texture of freeze-dried intact and restructured fruits: Formation mechanisms and control technologies

Owing to the growing demand for ready-to-eat food and the expanding food-processing sector, consumption of freeze-dried fruit food is increasing globally, holding significant market value. Texture is critical in determining the overall quality and consumer acceptance of freeze-dried fruit products. However, texture formation and control remain one of the least well-described quality attributes due to challenges from complex fruit matrices and testing methodologies, impeding advancements within the freeze-drying industry. Focusing on the two main types of freeze-dried fruit products (i.e., freeze-dried intact and restructured fruits), this review elaborates on the formation mechanisms and control technologies of the texture properties, primarily analyzing from the perspective of carbohydrates in fruits. Try to establish a porous scaffold model to clarify the dominant attributes of texture formation during freeze-drying, thereafter explain and compare the formation and control principles governing the texture of these two types of freeze-dried fruits. The porous scaffold of freeze-dried fruit is built by a polysaccharide network and small molecule sugars within glassy amorphous at sufficiently low water content, showing various macroscopic porous characterization. Three dominant attributes of texture formation are summarized, namely pore/cellular morphology, solids, and water content in the final freeze-dried fruit matrix. Most texture control techniques are based on the modification of these three dominant attributes. Furthermore, freeze-dried restructured fruits exhibit a greater texture enhancement potential than intact fruits due to the loss of cellular structure, providing new inspiration for the future development of personalized multi-functional freeze-dried snacks.