Cryo assisted spouted bed roasting of coffee beans

• Pyrolytic reactions lead to characteristic aroma and flavor during coffee roasting.
• Optimizing and controlling the roasting parameters is critical for coffee quality.
• Coffee roasting process involving spouted bed and cryogenic cooling was developed.
• Proposed roasting produces high quality coffee beans increasing its economic importance.

A process for roasting of coffee beans involving spouted bed roasting (SBR), followed by cryogenic cooling and grinding was developed. The temperature and time of roasting was 210 °C and 22 min. It was found that coffee subjected to SBR roasting followed by cryogenic cooling had greater impact on the retention of volatile compounds especially the furans and thiols than the conventional drum roasting (CDR). The dehydration, the zero and first order color degradation rate constants for cryo treated SBR coffee beans were found to be 0.079, 1.9 and 0.04488 respectively where as for CDR coffee beans it was 0.03942, 1.398 and 0.030 correspondingly. The sensory analysis confirmed that proposed roasting method was beneficial for the retention of volatile flavor compounds and reduction of the burning of surface, and will be very useful for coffee processing in order to produce high quality coffee beans and increase its economic value.Industrial relevancePyrolytic reactions lead to characteristic aroma and flavor during coffee roasting. Optimizing and controlling the roasting parameters is critical for coffee quality. Coffee roasting process involving spouted bed and cryogenic cooling was developed. Proposed roasting produces high quality coffee beans leading to its improved economic importance.