2002 Annual Report
Research
Improvement in Thermal Processes for Foods
Mrinal Bhattacharya, Professor
Ajay Pal Singh, Graduate Student
Funding Source
Minnesota Agricultural Experiment Station
Objective
The objective of this research is to evaluate rheological behavior and
constitutive equations for food products. These constitutive equations
can be used in simulations during various processing operations.
Project Description
The formation of foams, such as bread dough, involves bubble nucleation
and growth, microphase separation, rupture of thin films, and finally
gelling. The reaction and buildup of mechanical properties will be monitored
using flooded parallel plate geometry in a rheometer. In order to simulate
the bread baking process, the temperature as a function of time was monitored.
The dough was placed in an oven and temperature at several points was
recorded in a computer as a function of time. A self-tuning temperature
controller was used to control the temperature of the rheometer in the
exact rate as the baking process. A previously recorded temperature profile
for the formulation to be studied, with data spaced every 0.5 seconds,
was used as a moving set point for the heaters. The rheometer was operated
in the dynamic mode; the measurements of storage and loss moduli were
obtained at different frequencies and strains to obtain the maximum differences
between measurements of samples of differing compositions (gluten content,
gluten/starch ratio, and water content).
Results
Some initial studies have been conducted. There appear to be distinct regions of modulus development such as starch gelatinization and bubble formation before a plateau modulus is reached. Data collection is in progress and will be completed by spring 2003.