Rheological properties of stabilizers at low temperatures in concentrated sucrose solutions

Véronique Masselot (1, 2) , Hayat H. Benkhelifa (1, 2) , Gérard Cuvelier (2) , Véronique Bosc (2)

1 UR FRISE - Génie des procédés frigorifiques pour la sécurité alimentaire et l'environnement
2 SayFood - Paris-Saclay Food and Bioproduct Engineering

During the freezing of sorbets, the concentration of sucrose and stabilizing macromolecules increases in the unfrozen phase. Rheological properties of this unfrozen phase were studied, depending on nature and concentration of hydrocolloids in sucrose solutions at temperatures below zero. Three stabilizers were tested individually in sucrose-rich solutions: locust bean gum (LBG), hydroxypropylmethylcellulose (HPMC) and carboxymethylcellulose (CMC). The parameters of the Ostwald-de Waele model were determined and apparent viscosities of solutions were calculated at shear rates encountered during the process. Intrinsic viscosities and critical concentrations of entanglement were determined to evaluate the expansion of polymers in solutions and the transition of concentration regimes according to process conditions. Viscoelastic properties were also tested to study the possible cryogelation. For HPMC and LBG, the shear thinning behavior increased quite linearly with the concentration in stabilizer whereas CMC was highly shear thinning. Increasing sugar did not reveal large effect on these properties. The increase in apparent viscosity of the unfrozen matrix in process conditions was dependent on stabilizers; solutions containing LBG were less viscous than the others. Intrinsic viscosities revealed that HPMC and LBG became progressively less expanded as the concentration of sucrose increased whereas CMC tended to aggregate. Measurements of viscoelastic properties evidenced a dominant viscous behavior for HPMC and LBG systems whereas CMC systems showed dominant elastic behavior at frequencies higher than 0.1 Hz. The next challenge will be to better understand the potential link between the particular rheological behavior of hydrocolloids in process conditions and their possible influence on crystallization mechanisms.

Mots clés: Carboxymethylcellulose; Hydroxypropylmethylcellulose; Locust bean gum; Stabilizers; Rheology; Sorbet

Domaines: Sciences de l'ingénieur [physics]; Sciences de l'environnement

Véronique Masselot, Hayat H. Benkhelifa, Gérard Cuvelier, Véronique Bosc. Rheological properties of stabilizers at low temperatures in concentrated sucrose solutions. Food Hydrocolloids, 2020, 103, pp.105691. ⟨10.1016/j.foodhyd.2020.105691⟩. ⟨hal-03177529⟩