Specific Heat Capacity Measurements of Frying Oil Using Modulated Differential Scanning Calorimetry

With standard differential scanning calorimetry (DSC), it is possible to derive calorimetric data for equilibrium or metastable samples. The introduction of temperature-modulated DSC (TMDSC) permits in its quasi-isothermal (non-scanning) mode (TMDC), long-time apparent heat capacity measurements of high precision (±1 %). For flexible molecules, heat capacity measurements from the various calorimetric methods could be combined in the ATHAS Data Bank, which now contains experimental data for over 200 materials. These data were linked to the vibrational and large-amplitude motion of the constituent atoms and molecules, to provide a base for the judgement of the thermal analyses, extending outside the range of equilibrium or metastability with an error of only 2-5 %. The TMDC together with DSC is now able to quantitatively assess the reversibility of thermal processes. A sufficient number of systems have been analyzed in this fashion to develop better understanding of macro-, micro-, and nanophases of flexible macromolecules. The new concepts discussed are: (1) multiple glass transitions due to possible rigid-amorphous fractions (RAFs) and glass transitions within crystals, both observed in semicrystalline macromolecules, and (2) locally reversibly melting on the surface of chain-folded crystals. The locally reversible melting decreases with crystal perfection and also disappears when the chains become rigid.

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THE STUDY OF THERMAL DENATURATION OF BEEF, PORK, CHICKEN AND TURKEY MUSCLE PROTEINS USING DIFFERENTIAL SCANNING CALORIMETRY

Theory and practice of meat processing ◽

10.21323/2414-438x-2019-4-3-19-23 ◽

2019 ◽

Vol 4 (3) ◽

pp. 19-23

Author(s):

Irina V. Agafonkina ◽

Igor A. Korolev ◽

Taras A. Sarantsev

Keyword(s):

Differential Scanning Calorimetry ◽

Heat Capacity ◽

Specific Heat ◽

Specific Heat Capacity ◽

Thermal Processing ◽

Thermal Denaturation ◽

Meat Product ◽

Muscle Proteins ◽

Scanning Calorimetry ◽

Denaturation Process

In the temperature range from 45 °C to 90 °C the process of thermal denaturation of a whole complex of muscle proteins in meat takes place. An effective mode to register the thermal denaturation process is the method of differential scanning calorimetry (DSC). As a result of studies the differences during the process of thermal denaturation of muscle proteins of pork, beef, chicken and turkey were defined by the appearance of endothermic peaks in DSC thermograms. The main variances are associated with the process of denaturation of myosin and sacroplasmic proteins and indicate indirectly their quantitative ratio in meat. The values of effective specific heat capacity in the temperature range from 20 °C to 90 °C are obtained as well as those of heat spent on the denaturation process.At reheating, the values of specific heat capacity increased by 0.1 J/(g*K) on the average, and peaks of thermal denaturation were not detected, that certifies the irreversibility of the denaturation process and the decrease in the bound moisture proportion in meat after thermal processing. Knowledge of the nature of protein thermal denaturation of each kind of meat product is one of the necessary tools for developing the technology of meat product thermal processing.

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