Experimental data and predictive equation of the specific heat capacity of fruit juice model systems measured with differential scanning calorimetry

Abstract

Specific heat capacity (CP) is regarded as a fundamental parameter for the design, operation, and optimization of the heat transfer equipment widely used in the food industry. Using the calorimetric ASTM E1269‐11 standard procedure, the CP–temperature (CPfalse(Tfalse)) curves of fruit juice model systems prepared at different mass fractions of fructose/glucose/sucrose/citric acid/pectin and water were measured. Thus, experimental data of CP for solid samples in crystalline and amorphous states from −80 °C up to the melting temperature range and for aqueous samples from −80 to 110 °C were generated. In the tested temperature interval, the CP of crystalline, amorphous, and aqueous samples were found to be in the ranges of 0.037 ± 0.020 to 5.61 ± 0.04; 0.061 ± 0.004 to 3.12 ± 0.19, and 0.363 ± 0.05 to 3.24 ± 0.14 kJ/kg °C, respectively. Also, a generalized empirical equation based on the type and concentration of components was developed to predict the CPfalse(Tfalse) curves of the studied samples. The proposed equation exhibited a low error sum of squares (SSE < 57.3) and a high coefficient of determination (R2 > 0.927). An analysis of variance (ANOVA) was performed with a confidence level of 95% (p < 0.05). The CPfalse(Tfalse) curves were influenced by temperature, thermal transitions, water, solid types, and compound interactions. Glucose was one of the solids that most significantly influenced the CP values of samples. Practical Application The experimental specific heat capacity data and empirical equation proposed in this study are relevant to the design, evaluation, and optimization of heat transfer equipment involved in many foods and biochemical industrial processes such as cryopreservation, frozen storage, freezing, chilling, drying, and the cooking of hard candies.

Physical and Rheological Properties of Pomegranate Juices and Concentrates

“…The first part is characterized by a linear decrease of the concentrate temperature (in t°C) of 20°C until reaching the freezing (eutectic). point of the concentrates at -25°C Δt f = 1.86 (n) ….. (7) . where (n) the number of solute moles (M=180) dissolved in 1000 g of solvent (water).…”

“…Specific heat (Cp), is highly dependent on the water content, temperature, and chemical composition of food products. Thus, detailed knowledge about the specific heat capacity (Cp) of food products over a broad range of temperatures is required for the heat transfer equipment (7). Specific heat values between 3.…”

Data Reconciliation As A Key To Enable Digitalisation Of Agrifood Industrial Processes: A Preliminary Case Study

“…By inserting the reconciled steady-state conditions, the heat exchanges (process enthalpy), based on mass and energy balances, and thermodynamics, allow getting information about vapor-liquid equilibrium and heat transfer. Detailed knowledge about the specific heat capacity of food products is required for the design, performance evaluation, operation, and optimization of the heat transfer equipment [22]. In addition to water content, soluble solids, such as sugar, pectin, organic acids, water-solute, and solute-solute interactions play an essential role in the values of sugar-rich systems like juices [22].…”

“…Detailed knowledge about the specific heat capacity of food products is required for the design, performance evaluation, operation, and optimization of the heat transfer equipment [22]. In addition to water content, soluble solids, such as sugar, pectin, organic acids, water-solute, and solute-solute interactions play an essential role in the values of sugar-rich systems like juices [22]. The assumption used for this work was to consider the orange juice as a mixture of just water and sugars, i.e., glucose, fructose, and sucrose.…”