Confectionery gels: Gelling behavior and gel properties of gelatin in concentrated sugar solutions

Gummies are gelatin-based confectionery gel products where the sweeteners play vital roles in the product texture. This study focused on the impacts of sweeteners, which make up ~70–80% of the total solids, on the sol properties, gelling, and melting behaviors of gelatin (4–6%) gels. Gelling and melting properties of gelatin solutions with and without sweeteners (sucrose and glucose syrup) were characterized with rheology and differential scanning calorimetry, while the final gel texture and surface properties were analyzed with texture analyzer and tensiometer. In contrast to the plain systems without sweeteners, which gelled at around 22 °C and melted at 35 °C, the high-sweetener systems exhibited coil-to-helix transition at a higher temperature level, and the subsequent sol-gel transition depended greatly on the bulk viscosity. Below the sucrose-syrup level of 75.9%, the transition was observed at 34–43 °C; higher levels of saccharides postponed or inhibited the transition. The internal interactions of high-sugar gels were considerably weaker than the plain gels, suggesting smaller and more dispersed junction zones. The quantities of melting enthalpy and internal interactions increased with gelatin concentration but decreased with sucrose-syrup level, due to the high viscosity. Gel surfaces were generally hydrophobic (non-polar) except for the 4% gelatin gels, whose surface polarity increased with sugar level. Gel hardness and tackiness increased with gelatin concentration but did not change significantly with moisture/sugar content at 5–6% gelatin.