| Thermal
analysis is group of techniques in which a physical property (e.g.
heat content, rigidity, weight, volume) of a sample is monitored
against time or temperature while the temperature of the sample,
in a specified atmosphere, is programmed.
Our equipment includes a differential
scanning calorimeter (DSC), a dynamic mechanical
analyzer (DMA), and an isothermal titration
calorimeter (ITC). The equipment is available for use by campus
personnel for a small fee and arrangements can be made for outside
contract work.
Projects we have performed in this lab include
determining gelatinization temperatures of starches, temperatures
and enthalpies of protein unfolding, melting of processed cheese
products, glass transitions in caramels and dried sweet potatoes,
melting and oxidation of lipids, and measuring specific heat for
a variety of food products.
Penny
Amato
Penny has been the manager of the Thermal Analysis Lab for over
10 years. She regularly attends Thermal Analysis short courses
and meetings. She is a member of the North American Thermal
Analysis Society (NATAS) and the International Confederation of
Thermal Analysis and Calorimetry (ICTAC). Her role in the
laboratory is to conduct experiments and/or train new users in
thermal analysis techniques primarily using differential scanning
calorimetry but also using dynamic mechanical analysis and titration
calorimetry. She assists in research projects by developing the
appropriate sample preparation, test methods and running conditions
to achieve the research objectives.
Brian
Farkas
Dr. Farkas is a food engineer and the principal investigator of
the Thermal Analysis Lab. His main research interest is transport
phenomena in foods and their effect on food safety, quality, and
processing efficiency. His research uses the thermal properties
of foods and packaging materials to simulate and optimize a multitude
of heating related operations including frying, microwave cooking,
convection heating, CO2 cooling, freezing, thawing, and drying.
 Differential
Scanning Calorimetry is a technique used to study heat (energy)
released or absorbed by materials when subjected to a temperature
program.
Perkin Elmer DSC 7 with Pyris Software
Temperature Capabilities: -70ºC
to ~500
Calorimetric Precision: ± 2%
Sensitivity: ·H · 0.1 J/g; Peak Height ·
0.1 mWatt
Typical Measurements made with the DSC
Melting temperature and heat of fusion (Oils/Fats/Lipids,
sugars, plastics, water)
Crystallization temperature and heat of crystallization
Protein Denaturation-- (Fairly concentrated samples only)
Starch Gelatinization
Specific Heat
Glass Transition
“Bound” Water
Oxidation of Oils
Dynamic mechanical analysis is a technique to
measure a sample’s physical response to an oscillating force
when subjected to a temperature program. It is generally
used for solid or semi-solid samples. It can also be run
at constant stress, constant strain and/or constant temperature.
 Perkin
Elmer DMA 7 with Pyris Software
Temperature Capabilities: -40ºC to ~200
Minimum Force · N; Maximum Force · N
Measuring Systems
Parallel Plate
Extension
3-Point Bending
Single Cantilever
Dual Cantilever
Dilatometry
Testing Methods
Thermomechanical Analysis (Static Stress)
Stress/Strain Curves
Stress Relaxation
Creep Recovery
Rigidity/Temperature scans
Frequency Scans
Typical Measurements obtained with DMA
Yield Point, Shrinkage, Expansion, Strength
Phase transitions (Curing, Gel Point, Rubber/Glass Transitions,
Leathery Region)
Viscoelasticity, Toughness, Ductility, Damping
Plateau Regions, Master Curves
 Isothermal
titration calorimetry is used in thermodynamic analyses of macromolecular
interactions in solutions. The measured heat, either absorbed
or released upon chemical binding is used to calculate binding
constants, enthalpy, entropy, and stoichiometry of the reaction.
*Microcal Omega Reaction Cell with Origin
Software
Sensitivity typically in the micromolar range
for proteins
Sample cell volume is approximately 1.3 mL
Injection syringe contains about 290 µL of titrant.
Temperature range of 2 ºC to 90 ºC
* This is an older instrument that was donated
to the lab several years ago. We have not used it yet, but
are very interested in helping anyone who has an interest in getting
it running.
Typical Uses for ITC
Ligand binding
Enzyme Kinetics
Characterization of molecular structure and function
Food Science Thermal Analysis Laboratory
Room 231 Schaub Hall
Campus Box 7624
North Carolina State University
Raleigh, NC 27695-7624
Phone: (919) 513-2097
Email: Penny Amato
(pmafs@ncsu.edu)
|
