The rheological behavior of apricot puree measured in shear rate
range 0.0 to 100 s-1 and Oscillatory tests were studied at a wide range of
temperatures (0 - 50 °C) using a Physica UDS 200 rheometer. The results
indicated that the apricot puree behave as non-Newtonian fluids (pseudoplastic)
and have a definite yield stress. The relationship between (ηeff) and temperature
of apricot puree was examined. High correlation was found between (ηeff) and
temperature. The ηeff decrease with increase in temperature. Oscillatory test data
revealed weak gel-like (dispersion structure) behavior of the apricot puree:
magnitudes of G´ were higher than those of G´´, and both increased with
Oscillatory frequencies. The effect of temperature on their viscosity can be
described by means of an Arrhenius-type equation. The flow activation energy
for viscous flow depends on the chemical composition. Chemical and physical
tests for apricot puree were made. On the other hand, the mechanical properties
for apricot fruits were studied by using Instron Universal Testing Machine
model 4301. The effects of storage at different temperatures on physicomechanical
properties were studied by using the flat plate compression test and
penetration test. Maximum force (N) and elastic modulus values (MPa)
decreased with increasing storage time. Maximum force, Young’s modulus and
energy for apricot fruit were decreased in the non chilled condition and with
increasing storage time. |
