Temperature Effects on Thermodynamic Parameters and Solubility of Curcumin O/W Nanodispersions Using Different Thermodynamic Models

Abstract

Solubility of curcumin at different temperatures is of great importance in subcritical water extraction systems. We newly developed an approach for the solid–liquid equilibrium under subcritical condition to determine the solubility of curcumin. The experimental results were correlated successfully with thermodynamics models such as Van’t Hoff, modified Apelblat equation, Wilson, non-random two-liquid (NRTL) and λh equation and the interaction parameters’ values of curcumin-water were acquired. Good agreement between the experimental and calculated values with λh equation was observed at different temperatures (373.15–433.15 °K) at 1.5 bar. The obtained value of the relative average deviation was 2.29 × 10–5. The molar enthalpy (ΔH0), entropy (ΔS0), Gibbs energy (ΔG0) and their relative fraction of the total process were calculated. The calculated enthalpy with the Van’t Hoff equation (25.32 kJ/mol) agreed well with the differential scanning calorimetry analysis data (26.15 kJ/mol).

Effect of Adding Curcumin on the Properties of Linseed Oil Organogels Used as Fat Replacers in Pâtés

“…Both the gel formation as well as the proper dissolution of curcumin were evaluated by PLM. As it is already known, the melting temperature of curcumin is 175.1 °C [ 36 ], while the melting temperature of the beeswax is as low as 61.7 °C ( Table 1 ). Preliminary studies, where beeswax and curcumin were dissolved by heating over the melting point of the beeswax (70 °C), were not successful.…”

Preparation of Curcumin Nanodispersions Using Subcritical Water – Screening of Different Emulsifiers

“…According to literature, 20 mg curcumin powder was dissolved in 1.5 g emulsifier under constant stirring (300 rpm) for 15 min [16,17,19]. After that, the oil phase was added dropwise to 98.5 g distilled water as an aqueous phase and was stirred for 2 h. The obtained mixture solutions were placed in a sealed Teflon autoclave and heated at 120°C for 2 h in an oven (Behdad Medical Production Co., Tehran, Iran) where the internal pressure of the autoclave was 1.5 bar [18,19]. The Teflon autoclave with a capacity of 100 mL was designed and manufactured in our research laboratory.…”

“…For evaluation of the antibacterial activity of the prepared curcumin nanodispersions, the well diffusion procedure was carried out as described in a previous study [19]. An amount of 0.1 mL of the prepared S. aureus (Gram-positive) and E. coli (Gram-negative) colloidal solutions, based on 0.5 McFarland standard, were inoculated on a PCA medium and, then, several holes were created in the set agar.…”

“…It seems that a highly stable nanodispersion preparation with small particle size and narrow particle size distribution, under subcritical water conditions, is a suitable technique. In fact, subcritical water, under higher temperature and pressure of 100°C and 1 bar, respectively, is in liquid state but its polarity turns into methanol and ethanol [18,19].…”

Hydrothermally extraction of saponin from Acanthophyllum glandulosum root – Physico-chemical characteristics and antibacterial activity evaluation

“…Subcritical water is well-known as pressurized water (pressure of higher than 1 bar) with high temperature (higher than 100 °C) which has its liquid state at the mentioned conditions and its polarity leads into ethanol and methanol and increases the extraction yield [ 13 ]. These conditions can be rapidly provided in a laboratory autoclave and can be easily scaled up for industrial applications.…”