In condensed hydrocolloid systems, the mechanical glass transition temperature (T_gm)determined rheologically successfully captures the contributions of a network forming biopolymer to the material’s vitrification behaviour¹. In high solid hydrocolloid/co-solute model systems, it has been shown that the arrest in segmental relaxation at T_gm coincides with an arrest of small molecule diffusivity², underscoring the potential of this method in the production of controlled-release functional foods. This idea has recently been expanded upon to also define T_gm as an index of quality control, showing that lipid oxidation kinetics are contingent upon the availability of the system’s free volume, and that the T_g defined calorimetrically ( T_gc) appears unsuitable to capture the onset of segmental motion in such mixtures^3,4.

The present work therefore expands on these ideas, now examining whether T_gm can also be used as an index to control the rate of Maillard browning in model food systems. It proposes that there will again be predictive differences between T_gc and T_gm , suggesting that T_gm better represents the entirety of the system’s physical state. To achieve this, the glass transition temperature of porcine gelatin in the presence of glucose syrup and glucose are derived rheologically and calorimetrically. Upon characterising these temperatures, samples are stored at T> T_gm and T_gm>T> T_gc and the extent of Maillard browning in these systems is quantified.

Results demonstrate that there is an increase in browning at T>T_gm, but a much less pronounced response atT_gm>T>T_gc. This highlights the ability of T_gm to capture the onset of chemical reactivity and again underscores its utility for quality control. Overall, this work further emphasises the importance of accurately characterising the physical state of polymeric systems and may be applied to a range of food and nutraceutical engineering applications in which greater constituent control is necessary.

References

1. Kasapis, S. (2006). Definition and applications of the network glass transition temperature. Food Hydrocolloids, 20(2–3), 218–228. https://doi.org/10.1016/j.foodhyd.2005.02.020
2. Paramita, V. D., & Kasapis, S. (2019). Molecular dynamics of the diffusion of natural bioactive compounds from high-solid biopolymer matrices for the design of functional foods. Food Hydrocolloids, 88 , 301–319. https://doi.org/10.1016/j.foodhyd.2018.09.007
3. Ikasari, D., Paramita, V. D., & Kasapis, S. (2023). Mechanical vs calorimetric glass transition temperature in the oxidation of linoleic acid from condensed κ-carrageenan / glucose syrup systems. Food Hydrocolloids, 146 , 108555. https://doi.org/10.1016/j.foodhyd.2023.108555
4. Ikasari, D., Paramita, V. D., & Kasapis, S. (2025). The effect of mechanical glass transition temperature on the oxidation rates of omega fatty acids in condensed biopolymer matrices. Food Chemistry, 464 (Part 1), 141613. https://doi.org/10.1016/j.foodchem.2024.141613