Calcium effect on viscoelastic properties of fortified vegetable matrices

DOCTOROVICH, ROMINA S.; MARTÍNEZ, VANESA Y.; SALVATORI, DANIELA M.; ALZAMORA, STELLA M.

Puerto Vallarta, México.

Congreso; V Congreso Iberoamericano de Ingeniería de Alimentos.; 2005

Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Universidad de las Américas-Puebla (México), CYTED, etc.

The effect of Ca++ on the viscoelastic behavior of apple and potato tissues using different tests (uniaxial compression, oscillatory shear and creep) was analyzed.  All samples showed a viscoelastic solid behavior with the storage modulus (G´) dominating the viscoelastic response. Treated apple samples with or without Ca++ showed a decrease in rupture forces (Frup) and a pronounced decrease in G´ as compared with fresh tissue. Initial compliance (J0) and decay compliances (J1 and J2) significantly increased after the treatments while retardation times were approximately constant. The lower values of J0 and the slight recovery of Frup obtained at long times in samples treated with Ca++ at atmospheric pressure revealed a recovery of the tissue.  Analysis of potato tissue subjected to heat treatments indicated that, when Ca++ was present in the solution, G´ values and creep parameters were, in general, more similar to those of raw tissue when compared to samples heated only in water.