Determination of glass transitions in boiled candies by capacitance based thermal analysis (CTA) and genetic algorithm (GA)

The glass transition temperature (T-g) is an important property that influences the processing and textural characteristics of candy. Measurement of T-g is done by comparably expensive and complex instruments. In this study, we tested a new system which uses capacitance thermal analysis (CTA) of candy trapped between stainless plates, as the system is caused to heat at an uncontrolled rate. The data of capacitance as a function of temperature were processed by a genetic algorithm (GA), and fitted to a three-section model to determine T-g. T-g of the candies were independently measured by DSC as a reference. The results showed that when the T-g of the candy was below similar to 15 degrees C, the measurement from the GA-CTA was higher (2-3 degrees C) than that from DSC. However, if T-g of the candy was higher than 15 degrees C, the two methods gave similar values. GA based CIA provides a feasible new way to measure phase transitions in candies with relatively inexpensive equipment, and with less need for user interpretation of data. (C) 2016 Elsevier Ltd. All rights reserved.