Gouveia Julia Rocha, de Lira Lixandrão Kelly Cristina, Tavares Lara Basílio, Lixandrão Fernando Paulo Henrique, Garcia Guilherme Elias Saltarelli, Dos Santos Demetrio Jackson
Nanoscience and Advanced Materials Graduate Program (PPG-Nano), Federal University of ABC (UFABC), Santo André 09210-580, Brazil.
Center of Engineering, Modeling, and Applied Science (CECS), Federal University of ABC (UFABC), Santo André 09210-580, Brazil.
Foods. 2019 Oct 2;8(10):449. doi: 10.3390/foods8100449.
For the first time, the novel experimental technique Temperature Modulated Optical Refractometry (TMOR) was employed for cocoa butter thermal transitions characterization. The average refractive index (N), the volume (v) change, and the volumetric expansion coefficient ( β q ) as well as the dynamic quantities β ' and β ″ (real and imaginary volumetric expansion coefficient, respectively) were monitored during cooling and heating and compared to the heat flow curves obtained via the standard technique dynamic scanning calorimetry (DSC). The investigation of these quantities showed that TMOR analysis can yield not only thermal transitions temperatures that are comparable to DSC results, but also some new thermal events that are not detected by DSC. This outcome suggests that TMOR might provide some additional insights on cocoa butter melting and crystallization by means of frequency-dependent measurements due to temperature modulation. This new information that can be accessed during temperature ramps might provide a deeper insight into thermal behavior of fat-based foods, evidencing TMOR value as a tool for thermal transitions investigation.
首次将新型实验技术温度调制光学折射法（TMOR）用于可可脂热转变特性的表征。在冷却和加热过程中监测了平均折射率（N）、体积（v）变化、体积膨胀系数（βq）以及动态量β'和β''（分别为实部和虚部体积膨胀系数），并与通过标准技术动态扫描量热法（DSC）获得的热流曲线进行了比较。对这些量的研究表明，TMOR分析不仅可以得出与DSC结果相当的热转变温度，还能发现一些DSC未检测到的新热事件。这一结果表明，由于温度调制，TMOR可能通过频率相关测量为可可脂的熔化和结晶提供一些额外的见解。在温度变化过程中可获取的这些新信息可能会更深入地了解基于脂肪的食品的热行为，证明TMOR作为热转变研究工具的价值。
