Investigation of the Effect of Cocoa Roasting Temperature and Time on Total Polyphenols, Chemical Properties and Sensory Properties of Cocoa Powder

Roasting is an important step in cocoa bean processing. Heating leads to the formation of many beneficial properties of cocoa such as flavor, color, texture. However, these positive changes can also be accompanied by reactions that reduce the content of active compounds such as polyphenols. Polyphenols have positive therapeutic properties and are associated with the nutritional value of cocoa, but they cause a feeling of bitterness and have a negative effect on the flavor of cocoa. Therefore, it is important to choose the suitable conditions for roasting cocoa. The aim of this study was to investigate the effect of roasting parameters (temperature, time) on chemical, sensory, color and phenolic properties of cocoa powder. In the present study, temperature at three levels (120, 130 and 140 °C) and time at three levels (20, 30 and 40 minutes) were used for roasting. The results showed that with changing roasting temperature and times, browning index (OD460 / OD525) (P ≤ 0.05), polyphenol content and humidity reduced significantly (P ≤ 0.01). Roasted cocoa powder at 140 °C for 40 minutes showed the highest amount of browning index and sensory evaluation score and the lowest amount of polyphenols compared to other samples. Optimization of roasting process conditions had a significant effect on the acceptability, chemical and sensory properties and polyphenol content of cocoa.