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Thermorheological evaluation of gelation of gelatin with sugar substitutes

Tau, Terry, Gunasekaran, Sundaram
Lebensmittel-Wissenschaft + [i.e. und] Technologie 2016 v.69 pp. 570-578
gelatin, gelatinization temperature, gelation, glass transition temperature, glucose, loss modulus, storage modulus, sucrose, sugar substitutes, syrups, total solids
The effects of replacing sucrose with sugar substitutes in gelatin gels were investigated. Oscillatory shear tests were performed to determine the rheological properties of gelatin-glucose syrup-sweetener (GGS) gels. The sweeteners used were sucrose and commercial sugar substitutes, Splenda® and Equal®. Gelation temperature (Tgel) was determined at the crossover point of storage modulus and loss modulus, during temperature sweep. The use of sugar substitutes did not alter the gelation temperature of gels. However, the rheological data of GGS gels were not amenable to time–temperature superposition and hence WLF/free-volume theory was not applicable. The gelation kinetics was also investigated using differential scanning calorimetery (DSC). The glass transition temperature (Tg) for different GGS gels determined from the DSC data were similar, ranging from −25.0 to −32.4 °C. Uniaxial compression test results showed that gel made with sucrose was softer with modified measure of toughness of 49.1 J/m3 at 20% strain compared to corresponding values of 91.4, 74.3, and 94.8 J/m3 for gels made with Splenda®, Equal®, and glucose syrup, respectively. Based on the results from sol–gel/gel–sol transition studies, both Splenda® and Equal® could be good candidates to replace sucrose in gelatin products if suitable non-nutritive bulking agent is added to maintain total solids content.