Executive summary until October 2020 – year 2
(PhD duration: 1st February 2019 –31th January 2022)
The first year of the PhD work dealt with the systemic physicochemical analysis of powders
and their classification according to their reconstitution ability. It was achieved at the end of January
2020 with the following deliverables:
(1) Powder classification according to their reconstitution behavior,
(2) For selected powders: reconstitution kinetics in different conditions of temperature, stirring, etc.,
(3) First statistical correlations between the various powder characteristics and their reconstituability
Papers I and II, respectively submitted to Powder Technology and Journal of Food Engineering, are
related to year 1 deliverables (Annex 1).
Deliverables of year 2 (January 2020 – January 2021)
(1) Surface chemical mapping and nanoindentation to establish correlations with powder
(2) Determine the effect of surface modifiers (quantities to cover the surface, distribution at the particle
surface, minimal quantity necessary to improve wetting. etc.).
The second year of the PhD work should meet these two stated deliverables which are still in
progress due to the lockdown caused by the CoViD-19 health crisis. The work was focused on a powder
presenting a low wetting ability (i.e. whey protein powder) and coating was achieved with sugars. In
agreement with IFPRI partners, five sugars (i.e. sucrose, lactose, glucose, fructose, and galactose) were
chosen to cover a whole range of physicochemical properties: solubility, chain length, structure, glass
transition temperature, hydrophilicity…Links between powder reconstitutability (more particularly
wetting) and sugar nature, location, quantity, coating depth were thoroughly investigated (see take-home
message in Figure 1).
Deliverables of year 3 ((January 2021 – January 2022)
(1) Fitting of reconstitution kinetics followed by granulometric;
(2) Empirical models able to predict reconstitution times from powder physicochemical characteristics;
(3) Definition of a reconstitutability index reflecting powder reconstitution behavior independently from
reconstitution conditions in agitated vessels.
During the lockdown, the third year of the PhD work about modeling was started earlier than
scheduled as telecommuting was possible for these deliverables. Therefore, the first results of year 3 are
also presented into this report particularly in Annex 2.