Application of DSC in Starch Gelatinization
Differential Scanning Calorimetry (DSC) is widely used in the study of the physical properties of food. By measuring peak position, peak point, peak area, and other parameters, DSC can analyze the phase transition temperature, thermal enthalpy, crystallization temperature, melting point, etc. of food components. To understand the effect of gelatinization temperature on food quality and processing properties, DSC can be used to study and observe this endothermic phenomenon.
1. The Meaning of Starch Gelatinization
Starch gelatinization refers to the fact that when granular starch is added to a certain amount of water and heated, the starch particles absorb water and expand, the starch molecules begin to vibrate intensely, and the hydrogen bonds between the crystalline phase and the amorphous phase of starch molecules are disrupted.
2. Principle of DSC Application in Starch Gelatinization
DSC is used to detect that, as the temperature of the sample increases, the sample undergoes heating and an endothermic or exothermic reaction occurs in real time. When starch is mixed with water, the water forms a crystalline water structure chain with the starch molecular chain. When this structure exhibits significant endothermic melting peaks as the temperature rises, the melting temperature and heat absorption vary with different concentrations.
3. Working Method of DSC for Determining Starch Gelatinization
- Experimental equipment: DSC 600 Differential Scanning Calorimeter
- Sample preparation: Take 3 mg of wheat starch and place it in an aluminum crucible, then add 5 μl of water, mix, and seal it with a tablet press.
- Use of instruments: Calibrate the melting point and enthalpy value with standard indium metal for testing. Place the crucible with the sample on the right side of the tray and an empty covered control aluminum crucible on the left side. The temperature is set to 200 °C, the heating rate is 10 °C/min, and 50 ml/min of nitrogen is passed through for the experiments.
- Experimental curve: –
- Result analysis: When starch and water are simply mixed, there is no endothermic reaction between them. When the temperature reaches 88.0 °C, an endothermic phenomenon begins, the peak point is observed at 103.0 °C, and the sample’s endothermic absorption ends at 107.1 °C. The area of the entire endothermic peak represents the energy absorbed by starch gelatinization.
4. Experimental Results
The gelatinization temperature of corn starch was obtained using the sample and the empty control crucible, and the peak area indicates the degree of starch gelatinization. Corn starch has a higher gelatinization temperature, and after gelatinization testing, wheat starch, corn starch, and potato starch require more energy.
In addition to its application in the food industry, differential scanning calorimetry is also used in plastics, rubber, coatings, pharmaceuticals, metal materials, composite materials, and other industries.