State Diagram of Crystallized Date-Syrup: Freezing Curve, Glass Transition, Crystals-Melting and Maximal-Freeze-Concentration Condition

• Published in: Thermochimica acta Vol. 666; pp. 166 - 173
• Main Authors: Al-Farsi, Kutaila Abbas, Al-Habsi, Nasser Abdullah, Rahman, Mohammad Shafiur
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 10.08.2018
• Subjects: crystallization; date fruit; eutectic point; phase change; Sugar syrup; crystallization; phase change; date fruit; Sugar syrup; eutectic point
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/j.tca.2018.06.003

[Display omitted] •State diagram of crystallized date-syrup was developed using thermal analysis•Freezing curve, glass transition, and sugar crystal-melting curves were modeled by theoretical thermodynamic equations•Maximal-freeze-concentration was determined to estimate end point of freezing and un-freezable water content•Eutectic point was determined from the intersection of the freezing curve and solute crystallized line State diagram of crystallized date-syrup was developed based on the freezing curve, glass transition curve, sugar crystals-melting curve, maximal-freeze-concentration condition, and eutectic point. The freezing point, glass transition, and sugar crystal-melting curves were modeled by Chen’s model based on Clausius-Clapeyron equation, Gordon-Taylor equation and Flory-Huggins equation, respectively. The ultimate maximal-freeze-concentration condition was determined as -42.8 °C [i.e. (Tm′)u, end point of freezing curve]. The intersection point on the freezing curve from the vertical line passing through the end point of freezing [i.e. (Tm′)u] as Xs′ [i.e. 0.73 g/g sample (i.e. un-freezable water as 0.27 g/g sample)]. The eutectic temperature and solutes content at eutectic point were determined as -10.2 °C and 0.39 g/g sample, respectively.