Title : Plant-based food powders: Linking particle surface properties, glass transition, and powder functionality
Abstract:
Due to their high perishability and strong dependence on seasonal and climatic conditions, fruits and vegetables account for a significant proportion of food waste. Their fragility also contributes to their underconsumption, leading many populations to not meet the recommended nutritional intake. Many fruits and vegetable are processed into powder form to increase their shelf life and year-round availability. In powder form, stability and functionality are maintained only if storage conditions are adequate. However, powders are exposed to environmental conditions during transport and storage. Indeed, temperature and relative humidity can affect the behavior of powders, and therefore their quality. These parameters may also be responsible for physical changes, such as the glass transition, which corresponds to the transition from a glassy state to a rubbery state. Glass transition temperature (Tg) of fruit and vegetable powders is generally low (i.e.; ambient temperature), and they can become highly hygroscopic and sticky, impairing their functionality. Particle surface interacts directly with the environment, and its composition have a direct impact on physicochemical properties. Therefore, surface characterization of such powders is essential to propose ways of optimizing functional properties and guarantee good end of product quality, both at consumer and industrial levels.
The present work aims to investigate the behavior of plant-based powders under controlled storage conditions by mimicking environmental variations in temperature and relative humidity. Particular attention is given to the impact of these conditions on powder stability and functional properties in relation to glass transition phenomena. To this end, a multiscale characterization approach is employed to evaluate physicochemical and functional properties at different scales, including powder, particle, and surface levels. Functional properties such as flowability and wettability are studied alongside physicochemical characteristics, while particle surface properties are mainly investigated using Atomic Force Microscopy (AFM). Surface topography, roughness, and nanomechanical properties are analyzed to better understand how environmental conditions influence particle surface organization and, consequently, the macroscopic behavior of plant-based powders. These findings will contribute to a better understanding of storage-induced changes and may help optimize the stability and functionality of plant-based powders for industrial applications.
