Temperature dependency of viscoelastic properties of a Low-fat soft cheese after frozen storage.

MEZA, B. E.; DE PIANTE VICÍN, D.; VERDINI, R. A.; RUBIOLO, A. C.

Foz de Iguazu

Congreso; 16th World Congress of Food Science and Technology; 2012

International Union of Food Science and Technology (IUFoST).

The objective of this work was to analyze the temperature dependency of viscoelastic properties of a low-fat soft cheese after frozen storage. Commercial cheese bars were frozen and storage at -25 ºC during 33 days. After that, cheeses were thawed and stored at 6 ºC during 48 days for further ripening (frozen cheeses). Cheeses stored at 6 ºC during 48 days were used as control samples (control cheeses). Frequency sweeps (0.01-10 Hz) in the linear viscoelastic region at several temperatures (10, 20, 30, 40, and 50 ºC) were carried out in triplicate. Elastic modulus (G´), viscous modulus (G"), complex modulus (|G*|) and complex viscosity (|n*|) were determined. Time-temperature (TT) superposition was applied in order to analyze G´ and G" values. Weak gel model for foods (|G*|=AF*f^z) was used to study values of |G*|. Temperature dependency of |n*| at 1 Hz was analyzed with an Arrhenius type equation. Statistical analysis was done using ANOVA. TT superposition could be satisfactory applied to overlap G´ and G" values at low temperatures (10 to 30 ºC). Activation energy of |n*| for frozen cheeses was lower than control cheeses, suggesting lower resistant to break up of cheese microstructure. Weak gel model for foods parameters, z (number of interactions) and AF (strength of interactions), decreased as temperature increase from 30 to 50 ºC in both frozen and control cheeses. Also, z values of frozen cheeses were lower than values of control cheeses, suggesting that frozen cheeses presented lower number of interactions in control cheeses.