Thermal Analysis Curves of Foods

Thermal Analysis Curves of Foods and Food Additives 

Setaram micro DSC-III calorimeter cooling and heating rate 0.5 °C min sample mass ca 900 mg Nj atmosphere. 

The exothermic peak on the cooling DSC curves shifted to the higher temperature side with increasing polymer concentration. The endothermic peak on the heating DSC curves shifted to the higher temperature side and split into multiple peaks with increasing polymer concentration. 

1% sodium-type gellan gum solutions containing CaCl2 at various concentrations. 

---

This handbook is designed to provide general information on the basic principles of TA and a variety of its applications. It is composed of two 1915 parts. Part I deals with information on the transition, reaction and characteristic parameters of substances. It introduces general principles, data 1919 treatment, experimental procedures and data analysis. Part II presents about 1000 typical 1945 thermal analysis curves, with brief explanations, for a wide variety of materials, such as polymers, 1960s foods, woods, minerals, explosives, inorganic compounds, and their coupled simultaneous 1964 curves. TA charts have been contributed by Institutes and Universities in China. Part III cites 1965 various data tables relating to thermal analysis. 

In brief, a DSC instrument comprises two cells fixed in an adiabatic chamber. One cell contains the sample to be tested, the second cell contains a reference solution or an empty DSC pan. The adiabatic chamber is maintained under pressure to avoid the evaporation of the sample (Plum, 2009). A DSC-thermogram represents the plot of heat capacity difference ACp (between the sample and the reference) as a function of temperature. Thermodynamic parameters, such as T, AH and AS, could be determined by the DSC curve analysis. T is the temperature at which the concentration of denatured and native forms of the protein are equal. This specific temperature is also called the midpoint of the thermal transition. AH represents the enthalpy of thermal transition determined from the integration of the DSC curve. The entropy (AS) of the thermodynamic transition of the protein may be calculated from the integrated area under the curve of AC /T vs. T. The free energy (AG), which gives an indication of the protein stability, can also be determined at any temperature from the values of AH and AS (O Brien and Haq, 2004 Plum, 2009). Thermal and thermodynamic properties of proteins analyzed by DSC are greatly affected by the experimental conditions used, such as pH, salts, alcohols, and the presence of other food components (e.g., lipids, polysaccharides) (Grinberg et al, 2009). 

---