Thermal behavior prediction of food particulates under ambient and cryogenic conditions

This article describes experiments to quantitatively characterize the thermal effects of solid food particulates in terms of temperature increment as a function of particle size under ambient and cryogenic conditions using turmeric (Curcuma longa L.) as a model material. The log-normal function was used to characterize the thermal behavior. Cylindrical specimens of turmeric were impacted diametrally, and the resulting particle size distributions and cumulative volume fraction were measured by computerized inspection particle size analyzer. The various model parameters estimated under the said conditions, such as surface-volume ratio, energy density and combined strength parameter, were found to be in the range of 3.5 x 10³-1.14 x 10⁶ (m⁻¹), 2.4 x 10⁵-6.6 x 10⁷ J/m³ and 174.1-229.5 J/m², respectively. The temperature change ΔT (C) was calculated in terms of log-normal parameters and material properties such as the specific heat and local energy density. The calculated ΔT was plotted as a function of size of particles. Local temperature rise up to 114.5 and 67.2C was found for the particle size of 12 μm or lower for ambient and cryogenic conditions, respectively. A novel mathematical model has been proposed to correlate the size distributions of solid particles under fracture to the temperature changes. During the size reduction of solid food materials, intensive energy degradation into heat takes place during fracture before resulting into fragments. Because fracture is a rate process with random fluctuation of stresses, the thermal effects cannot be calculated from classical approaches. The article describes a novel approach to quantitatively characterize the thermal effects of solid food particulates in terms of temperature change as a function of particle size under different treatment conditions. These characterizations can serve as a principled basis for modeling effects in a field where classical approaches are not applicable. The proposed approach can also be extended to nanoparticle and molecular characterization, which otherwise necessitates the usage of expensive instrumentation and also in biological processing such as in cancer research wherein if the cell size and its material properties are known, it may be possible to control the temperature induced during cell division.