Thermo-Mechanical Properties of Soft Candy: Application
of Time-Temperature Superposition to Mimic Response at High
Received: 4 September 2017 / Accepted: 30 November 2017 / Published online: 7 December 2017
Springer Science+Business Media, LLC, part of Springer Nature 2017
Soft candy primarily consists of an amorphous sugar matrix with highly adhesive and cohesive characteristics, which is generated
by rapid cooling of a supersaturated sugar solution. The integration of fondant in soft candy leads to a partial recrystallization of
the amorphous sugar so that the dispersed sugar crystals disrupt the continuous amorphous phase; this lowers cohesiveness, and
creates a short texture that is responsible for a more brittle fracture. Final processing (e.g., cutting and packaging) is usually done
at temperatures between 25 and 45 °C and short time scale. This study analyzed the effects of temperature and time scale on
thermo-mechanical properties of different types of soft candy. The application of time-temperature superposition principle on
small amplitude oscillatory shear experiments resulted in master curves that covered a frequency window up to 10
rad/s, hence a
time scale that is relevant in rapid processing. The respective shift factors depend on material properties, and a main factor of
influence is the presence of a crystalline phase. Simple penetration and tensile tests give additional information on material
behavior, especially with respect to effects of temperature on adhesiveness and cohesiveness. The results of the study provide
support for further optimizing soft candy formulations to ensure rapid and undisturbed processing.
Keywords Soft candy
In foods, sugar is regularly present either dissolved in water,
dispersed as crystals, or immobilized in the amorphous state.
According to the state of sugar, confectionary products may be
classified in (a) gummies and jellies where sugar is dissolved,
(b) ungrained soft candy with amorphous sugar, (c) grained
soft candy with part of the sugar in crystalline form, and (d)
hard candy with sugar in the glassy state .
Soft candy comprises caramels, toffee and chewy candy.
Caramels and toffee consist of sucrose, glucose syrup, milk
solids, fat and emulsifiers , and are manufactured by
heating the mixture to approx. 118–125 °C to obtain a su-
persaturated sugar solution with a moisture content of 5–
10 g/100 g . Maillard reactions between milk proteins
and reducing sugars that occur at this temperature are re-
sponsible for the characteristic flavor and color of the prod-
ucts [2, 4]. The solution is then rapidly cooled so that the
molecules do not have enough time to arrange themselves
but solidify in a disordered amorphous rubbery state [5, 6].
Chewy candy that consists mainly of sucrose, glucose syr-
up, gelatin, fat and emulsifiers is pulled (i.e., stretched and
folded over alternately) after cooling with the aim to incor-
porate fine air bubbles .
From a microstructural point of view the highly viscous
amorphous matrix represents the continuous phase of soft
candy in which fat is emulsified, and in which protein ag-
gregates and air bubbles are dispersed [3, 7, 8]. Ungrained
soft candy is highly cohesive and adhesive, shows creeping
and hardly fractures during mastication . This system can
be modified by adding fondant, a saturated sugar solution
that contains small sugar crystals (approx. 10 μminsize)
Electronic supplementary material The online version of this article
(https://doi.org/10.1007/s11483-017-9506-3) contains supplementary
material, which is available to authorized users.
* Carolin Schmidt
Institute of Natural Materials Technology, Technische Universität
Dresden, Bergstrasse 120, 01062 Dresden, Germany
Food Biophysics (2018) 13:11–17