Effect of curing conditions on heat resistance in white chocolate

Heat-resistant chocolate is of much interest to confectionery companies for marketing in tropical areas. Methods exist to produce heat-resistant chocolate by exposing the product to high relative humidity (RH) and increased temperatures. The overall objective of this research project was to explore the curing of white chocolate (30% whole milk powder, 44% sucrose, and 26% cocoa butter) to make it heat resistant and able to be picked up at 33 and 55°C. The curing involved storing solid chocolate samples at 83% RH at 29°C for 1 week. Moisture content before and after curing was measured using the Karl Fischer technique. Force required to penetrate (hardness) was measured at 29°C using a texturometer. Curing samples of white chocolate bars at a lower relative humidity (50% RH at 18°C for 12 weeks or 50% RH at 29°C for 12 weeks) also resulted in a heat-resistant chocolate that exhibited internal structure, as monitored by SEM. The moisture content in heat-resistant milk chocolate increased from an average value of 0.84% to 4.6% during the curing process. Curing increased the penetration force, indicating the development of internal structure. This study showed that heat resistance in white chocolate can be achieved by curing solid chocolate samples at controlled humidity and temperature conditions.