Dynamic rheological and thermal characteristics of caramels

Small-amplitude dynamic viscoelastic properties of three different commercial caramel formulations were studied in the range of temperature and frequencies of 20–80 °C and 0.1–10 Hz, respectively, using a controlled rate rheometer. Dynamic shear results revealed viscous behaviour for caramel samples: magnitudes of viscous modulus (G″) were higher than those of elastic modulus (G  ′), and both increased with angular frequencies (ωω). Temperature significantly (P<0.05P<0.05) affected both G′ and G″; however, the change was insignificant at higher temperatures and frequency. Dynamic modulii-frequency data were adequately fitted by a power law-type relationship and regression parameters did not vary with temperature. Differential scanning calorimetry (DSC) was employed to examine the thermal transition of caramels. A shift in glass transition temperature (Tg) was noticed during thermal scanning (cooling and warming) of caramel samples. Melting and crystallization temperatures were varied among the caramels. Testing temperature and variation in compositions resulted in differences in rheological parameters, melting and crystallization temperatures of caramels.