Phase/State Transitions of Confectionery Sweeteners: Thermodynamic and Kinetic Aspects

Abstract

It has been said that the key to making high-quality candy is understanding and controlling the transitions of sugar. Whether found as crystal, glass, or fluid solution, sugars impart the texture necessary to distinguish one confection from another and to provide a unique experience to the consumer. In principle, the phase/state transitions of sugars are best understood through careful application of the phase diagram. However, many, if not all, confections are not at equilibrium, meaning that the phase diagram is simply a starting point for understanding and controlling the state of sugars. An understanding of the thermodynamic driving forces that push a confection towards equilibrium and the kinetic constraints that control the rate of approaching that equilibrium are key elements to creating products with the desired texture, quality, and shelf life. In this review, we summarize the thermodynamic and kinetic aspects of controlling phase/state transitions in sweeteners, with particular emphasis on applications to confectionery products.

The effect of intrinsic and extrinsic factors on moisture sorption characteristics of hard candy

“…Typically, sugar in hard candies exists in glassy (or amorphous) state, resulting in their clear, transparent appearance, and hard and brittle texture. Phase/state change of sugar to crystalline state or “graining” during storage could lead to significant changes in the products' characteristics, affecting their shelf‐life (Bund & Hartel, ; Hartel, Ergun, & Vogel, ). Absorption of moisture by metastable sugar glass, initially at the surface, leads to sugar's higher molecular mobility and reduction of glass transition temperature ( T g ), resulting in sugar crystallization (Bund & Hartel, ).…”

Sugar Crystallization and Glass Transition as Destabilizing Factors of Protein-Stabilized Emulsions

“…Solute crystallization was not found for the FRU and FRU:GLU systems (data not shown), which may be explained by the higher solubility of FRU in water. As summarized by Hartel et al, 28 the solubility of FRU in water at 20°C is 78.9% (w/w), whereas GLU solubility is 47.8% (w/w). In the systems investigated in our study, the high degree of supersaturation of GLU solutions could allow nucleation and crystallization despite of the high viscosity which could inhibit the crystallization process.…”

Application of differential scanning calorimetry to estimate quality and nutritional properties of food products

“…Therefore, the knowledge about phase transition is very important in order to control food processing and storage conditions. Changes in phase behavior of confectionary may occur during storage, usually with a negative effect on shelf-life (Hartel et al, 2011).…”