Prediction of Liquid Specific Heat Capacity of Food Lipids

Heat transfer analysis during hydrothermal treatment of mango

To export Mexican mango fruit, it is required to comply with phytosanitary regulations, which implies heat transfer. Foods are biological systems with a dynamic behavior and, when they are thermally processed, their thermophysical properties change with temperature. Suitable simulation of heat transfer with temperature-dependent thermophysical properties can provide proper estimations of temperature histories to perform heat penetration analyses. The objective of this study was to predict temperatures within mango and immersion times by varying the mass of the fruit and water temperature during hydrothermal treatments. Thermal conductivity, specific heat capacity, and apparent density of ''Kent'' mango peel and pulp were determined. Finite element analysis was used to simulate heat transfer within the mango. Thermal conductivity and density were different for peel and pulp, but thermal diffusivity for both materials was not different. Predicted temperature histories adjusted properly to experimental data throughout the heating process. This indicates that thermophysical properties as a function of temperature for mango peel and pulp, the convective coefficient, the finite element model, and the methodology used to perform the estimations can be useful in the design of hydrothermal treatments for mango. PRACTICAL APPLICATION: Proper simulation of heat transfer with temperature-dependent thermophysical properties during hot water treatments for mango can provide accurate temperature histories and profiles that allow the prediction of temperatures within the fruit or immersion times by varying the mass and temperature of the heating medium. This will allow a subsequent heat penetration study to predict larval mortality, facilitating the design of quarantine treatments.

Biodiesels Manufactured from Different Feedstock: From Fuel Properties to Fuel Atomization and Evaporation

Different from fossil diesel, biodiesels can be manufactured from different sources of biomass or animal fat. Each biodiesel manufactured from a certain feedstock consists of different fatty acid methyl esters (FAMEs). Its FAME types and fractions are unique and are solely controlled by the mother feedstock and not the manufacturing process. One key feature that makes biodiesels different from their fossil counterparts is the oxygen contained in biodiesels. The oxygen content, FAME types, and FAME fractions vary in a wide range among biodiesels made from different feedstock and this in turn affects the fuel properties and physical processes, including atomization and evaporation. An extensive analysis has been successfully carried out in this study to examine the role of oxygen content, carbon chain length, and unsaturation degree in different biodiesels and the influence of FAMEs on key fuel properties (heating value, cetane number, viscosity, and surface tension). Furthermore, some useful information related to (i) the morphology and density of fuel fragments derived close to the nozzle exit and (ii) drop evaporation is reported. The atomization characteristics are experimentally observed using a high-speed imaging technique developed earlier, while the evaporation study is theoretically conducted using the well-known D-square model. It shows that the oxygen in the biodiesel is directly linked to the carbon chain length and the number of double bonds in the fuel molecules as well as to the key fuel properties. The viscosity of biodiesels and their constituents has a certain impact on the morphology and population of fuel fragments derived in the breakup zone, while the thermal properties have a significant effect on biodiesel evaporation. The dependence of fuel properties on atomization at the downstream locations of the spray, where the breakup process has completed, is minimal.

Critical steps during the prilling process of molten lipids: Main stumbling blocks due to pharmaceutical excipient properties

Prilling by ultrasonic jet break-up is an efficient process to produce perfectly spherical microparticles homogeneous in size. However, the material properties could affect the manufacturability and the final product properties especially with lipid-based excipients which often exhibit complex structural properties. This work presents the characterisation of six lipid-based excipients differing by their melting point and polymorphic behaviour which were used to produce microspheres using a pilot-scale prilling equipment. The experimental results were compared to theoretical calculations, especially the droplet solidification time which is a key-parameter for this process. This work highlighted that monotropic polymorphism of excipients and supercooling effect have a significant impact on process parameters which should be considered with care during formulation design.