EFFECT OF HEAT TREATMENT ON THE RHEOLOGICAL PROPERTIES AND COLOR OF PUMPKINS (Cucurbita moschate)

Abstract

B.CEPPA, Curitiba, v. 33, n. 1, p. 87-97, jan./jun. 2015
EFFECT OF HEAT TREATMENT ON THE RHEOLOGICAL
PROPERTIES AND COLOR OF PUMPKINS (Cucurbita
moschate)
Keila de Souza Silva*
Carolina Castilho Garcia**
Javier Telis Romero***
Maria Aparecida Mauro****
The aim is to investigate the eff ects of stepwise blanching and its
combination with drying on rheological properties and change of
color in pumpkins (Cucurbita moschata). 1 cm thick samples were
immersed in water at 55 °C for diff erent times, followed by diff erent
holding times prior to inactivation of the enzyme (97 °C/5minutes).
Controled samples were obtained after blanching at 97 °C for 5
minutes. The texture and color of the samples were measured and the
rheological parameters calculated according to the Maxwell model.
The results showed that stepwise blanching for 40 minutes with 30
minutes of holding time provided samples with equilibrium modulus
of elasticity greater than the control samples. These parameters
were used as blanching pre-treatment to convective drying with air
at 60 °C and a velocity of 1.5 m/s for diff erent drying times. Stepwise
blanched samples showed fi rmer tissues than control samples after
drying. There were no signifi cant diff erences in the lightness and
redness of stepwise blanched samples and control samples during
drying.