| الملخص: | Lipids in the Ready-to-use Therapeutic Food (RUTF) comprise various types of triglycerides such as palmitic, oleic and linoleic acids. Dynamic studies of the dielectric properties such as impedance, permittivity and loss tangent of the triglycerides at different temperatures ranging from 25 to -30 °C and frequencies from 10-2 Hz to 5 × 106 Hz were performed by electrochemical impedance spectroscopy (EIS). The outcomes of EIS were associated together with the analysis of Fourier-transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) in order to analyse the dielectric signals obtained. As expected, FTIR results suggest the presence of saturated and unsaturated triglycerides of the palmitic, oleic and linoleic acids. Besides, there are absorbance bands of functional groups that reflect the presence of proteins. The dielectric relaxation and dielectric constant were evaluated from the impedance and permittivity spectra, respectively. The results imply the RUTF possesses long-range motion of dipoles against lower temperatures. The phase transitions observed in RUTF as indicated by the DSC cooling curve (crystallization), lead to the shifting of dielectric properties in impedance and permittivity. © 2023 IUPAC & De Gruyter.
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