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Determination of chocolate melting properties by capacitance based thermal analysis (CTA)

Tan, Juzhong, Kerr, WilliamL.
Journal of food measurement & characterization 2018 v.12 no.1 pp. 641-649
capacitance, chocolate, lipid content, melting, particle size, particle size distribution, rheology, rheometry, stainless steel, temperature, thermal analysis
In this study, a capacitance thermal analyzer (CTA) was designed and tested for measuring the melting properties of chocolates, and compared with those measured by DSC and dynamic rheology. Chocolates with different fat content and particle size distribution (PSD) were placed between stainless steel plates, while capacitance and temperature were monitored between 20 and 60 °C. The PSD did not influence the Tₒₙₛₑₜ (~ 25 °C) and Tₚₑₐₖ (33 °C) measured by DSC. However, samples with finer particles had lower Tₑₙd than those with coarser particles (36.59–37.28 °C). Varying fat content did not result in differences in the DSC melting curves. Samples with smaller particle sizes had lower temperatures at peak capacitance than those with larger particles, with peak temperatures ranging from 30.8 to 39.3 °C, while higher peak capacitance values (2.61–2.84 10⁻ ¹¹ F) were measured by CTA. Samples with higher fat content had lower peak temperatures (range 34.7–39.71 °C) but higher peak capacitance values (range 3.29–4.3 10⁻ ¹¹F). Values from the CTA were best correlated with results determined by dynamic thermal rheometry.