Relationship between rheological characteristics and structure of blanched and/or osmotically dehydrated apple in presence of calcium

摘要

Rheological properties of apple tissue during osmotic dehydration in a 22% w/w glucose aqueous solution with calcium lactate (0.1% w/w) were analyzed using oscillatory shear, creep-recovery and double compression tests. Both storage (G') and loss (G") moduli for fresh and osmotically dehydrated tissues showed a weaker dependence with angular frequency. All samples had a viscoelastic solid behavior with dominant G'. In general, instantaneous (J_0) and retarded compliances (J_1 and J_2) and steady-state fluidity (η_N) significantly increased as treatment proceeded. The texture parameters (fracturability, hardness 2, area1, cohesiveness, springiness, gumminess, masticability and deformability modulus) decreased for all treated tissues with respect to control. Osmotic tissues slightly increased its hardness during treatment because of the presence of calcium lactate. Clear correlations could be suggested between structure changes and some rheological parameters.