Glass transition in plant-based powders: Linking matrix complexity to functional stability

: Background Fruit and vegetable powders are increasingly used in food formulations due to their high nutritional value, natural origin, and relevance for clean-label product development. However, their production and stabilization remain challenging because of the intrinsic complexity of plant matrices and their high sensitivity to environmental conditions. Scope and approach This review provides a comprehensive analysis of the physicochemical and functional behavior of plant-based powders, with a particular focus on the role of glass transition temperature (Tg). It examines how compositional complexity (e.g., sugars, fibers, proteins) and environmental factors (temperature, water activity) influence molecular mobility, structural transitions, and powder behavior across processing, storage, and end-use. Key findings and conclusions Glass transition emerges as a key parameter governing powder stability and functionality. Water acts as a major plasticizer, lowering Tg and promoting transitions from a glassy to a rubbery state, leading to structural changes such as caking, stickiness, and loss of flowability. These multiscale transformations, from molecular mobility to particle structure and surface properties, directly impact functional properties such as reconstitution, hygroscopicity, and stability of bioactive compounds. Processing strategies, including drying technologies, grinding conditions, and formulation approaches, play a critical role in controlling Tg and maintaining powder performance. Overall, integrating composition, structure, and environmental conditions provides a framework for the predictive design of stable, functional, and sustainable plant-based powders.