Some recent advances in microstructural modification and monitoring of foods during drying: A review

• Use of pretreatment and drying to create microstructures is explored and discussed.
• Use of image analysis to monitor microstructural changes is also reviewed.
• Assigning values to microstructure allows its statistical analysis.

A number of changes food undergoes during drying are related, one way or another, to changes in its microstructure. An ability to modify the microstructure of a food material is therefore highly desirable as this would allow a food processor to either produce a product with the desired characteristics or prepare a product in a way that facilitates further processing. Microstructural modification can be achieved in a number of ways, including the use of appropriate drying techniques and conditions, with or without sample pretreatment. In this review, the use of selected pretreatment methods and drying technologies to create various microstructures is explored and discussed. Selected examples of microstructural modification by creating a more porous structure to produce highly-crisp fat-free snacks as well as a structure that facilitates the release of a compound from the food matrix and hence increased bioaccessibility and/or extractability of the compound are presented. Use of image analysis techniques to monitor the microstructural changes and a structure-quality indicator, which can relate the changes at the microscopic level to those at the macroscopic level, are also briefly reviewed.