The effect of blanching temperature (50, 60, 70, 80, 90 and 100°C) and
time (10, 20, 30, 40, 50 and 60 min) on mechanical and texture properties of potato
(Solanum tuberosum L.) tubers of the cultivars Spunta and Diamont (maximum force,
maximum deformation, hardness and softening) were studied. The mechanical
parameters were measured using the Instron Universal Testing Machine (Model
4401) equipped with: 5-mm diameter tip probe and flat plate probe (with 500, 1000
and 5000 N load cell) for penetration test and compression test. The magnitude of all
mechanical test parameters, maximum force, maximum deformation, hardness and
softening decreased with an increase in blanching time and temperature. Blanching
temperatures range of (50-60 °C), (70-80 °C) and (90-100 °C) caused minimal,
intermediate and rapid degradation, respectively. So that, some blanching treatments
were selected which have high softening degree to make puree from Spunta
cultivar’s. The rheological parameters for potato puree such as ( Consistency index,
10 RPM viscosity, apparent viscosity and yield stress) have high correlation
coefficient (r > 0.93 ) with softening degree of blanched potatoes. The regression
equations of some rheological parameters of processed potato puree on the
mechanical parameter softness were obtained at different blanching times at 100 °C.
Some chemical and physical properties for potato products were made