Effects of viscoelasticity on moisture sorption of maltodextrins

Analytical and numerical solutions of pore formation in elastic food materials during dehydration

“…However, for proteins we have shown that their elastic modulus changes with T g / T , the ratio of the moisture-dependent glass transition temperature and the actual temperature ( van der Sman et al, 2023 ), and for starch and maltodextrins we have shown that zero-shear viscosity and relaxation times also scale with T g / T ( Van der Sman et al, 2022 ). Accounting for viscoelasticity is important for modelling food drying, as it explains hysteresis of moisture sorption ( Meinders and Oliver, 2015 ) ( van der Sman, 2023 ) ( Hu et al, 2023 ), and thus that the elastic stresses need to be included in the driving force for moisture transport, as also shown in this paper. The increase of elastic modulus and relaxation times with decreasing moisture content explains the formation of a rigid skin/case hardening during drying, despite starting with a material fully in the rubbery state at the start of drying.…”

Pore development in viscoelastic foods during drying

“…For values of Z 0 , we follow the relationship we have found earlier for starch. 28 For biopolymers, we typically find G N = 10 8 Á Á Á10 10 Pa. 28,29,61,62 For our simulations, we assumed the maximal value: G N = 10 GPa, rendering t a E 1 at…”

“…14,15,26,28,77 This requires a generalization of the multimode Maxwell model. Recently, we have developed a first simple model along these lines, 29 which explains the hysteresis during moisture sorption of maltodextrins. The model proposed in this paper can easily be expanded to a multimode approach by introducing multiple internal variables A i for each viscoelastic relaxation mode.…”

“…10,24 The interplay between the pressure drop and time development of porosity also plays a role in the DIC treatment of non-predried mushrooms, 25 but this system is different from the above, as the mushroom is a porous system with high interconnectivity, while the other systems have closed pores. It is shown in multiple publications 14,15,[26][27][28][29] that these food materials must be treated as viscoelastic materials, which dissipated elastic stresses at a time scale shorter or comparable to the time scales of drying.…”