Thermal evaluation of sucrose-maltodextrin-sodium citrate bioglass: Glass transition temperature

Structural and Thermal Characteristics of Buriti Tree Gum (Mauritia flexuosa)

A polysaccharide was isolated from the exudate of a buriti tree trunk (Mauritia flexuosa). The molecular structure, thermal stability, morphology, crystallinity, and elemental composition of the product were investigated through spectroscopic techniques, such as Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR 1H and 13C), and energy-dispersive X-ray spectroscopy (EDS); thermogravimetric analysis (TG), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In addition to NMR molecular modeling studies, were performed to confirm the 1H and 13C chemical shifts to Gal and Xyl conformers. Buriti tree gum (BG) is an arabinogalactan, containing Rha, Ara, Xyl, and Gal, and degrades almost completely (98.5%) at 550 °C and has a maximum degradation peak at 291.97 °C, with a mass loss of 56.33%. In the temperature range of 255–290 °C, the energy involved in the BG degradation process was approximately 17 J/g. DSC indicated a glass transition temperature of 27.2 °C for BG, which had an irregular and heterogeneous morphology, with smooth or crumbling scaly regions, demonstrating the amorphous nature of BG that was confirmed by the XRD standard. EDS revealed the presence of carbon and oxygen, as well as calcium, magnesium, aluminum, silicon, chlorine, and potassium, in the BG composition.

Development of a Caramel-Based Viscoelastic Reference Material for Cutting Tests at Different Rates

Cutting speed plays a crucial role for the behavior during and the final quality of viscoelastic foods after cutting and is, in industrial applications, usually adjusted on an empirical basis. Although previous studies investigated the interplay between the time-dependent properties and cutting behavior of model systems on an elastomer basis, there is still a need to elaborate such cause-effect relations for real foods. The aim of this study was to establish a reproducible manufacture of model caramels on a laboratory scale and to investigate the influence of the compositional parameters, moisture, and solid fat content, as well as cutting speed, on cutting behavior. It was possible to visualize ductile-brittle transitions in cutting force profiles, with an increase in cutting speed resulting in effects similar to that induced by a decreasing moisture content or an increasing solid fat content. Quantitatively, the progression of both maximum force and cutting energy reversed when cutting speed increased and composition changed in favor of a more brittle behavior. This work provides the basis for further research on distinct loading phenomena observed during the cutting of foods and for numerical modeling of the cutting process.

Temperature/end point monitoring and modelling of a batch freeze-drying process using an infrared camera

Temperature monitoring and accurate drying end time determination are crucial for final product quality in vacuum freeze-drying of pharmaceuticals. Whether crystalline or amorphous solutes are used in the formulation, product temperature during ice sublimation should be kept below a threshold limit to avoid damage to the product structure. Hence, there is a need to continuously monitor product temperature throughout this process. Current monitoring tools, such as thermocouples and Pirani gauge pressure sensors, have several limitations such as affecting product dynamics or imprecise end point determination. In this work, a monitoring tool based on infrared (IR) thermography is used for batch freeze-drying processes. Batches using three different vial sizes, with up to 157 vials, were studied, allowing to extend and better describe the representativeness of IR thermography for this application. The detailed axial temperature profiles obtained through IR imaging allowed not only a comprehensive non-invasive temperature monitoring of the product, but also tracking of the sublimation interface. IR temperature measurements and primary drying end point determination were compared to standard methods and thus verified. Parameters important for freeze drying design space calculation, namely the global heat coefficient (K_v) and cake resistance to vapor flow (R_p), were also accurately estimated with the proposed method.