Microwave-assisted parboiling of high moisture paddy: A comparative study based on energy utilization, process economy and grain quality with conventional parboiling

Highlights: • A novel approach of using high moisture paddy for parboiling was reported. • MWP and CP were compared based on energy utilization and process feasibility. • Specific energy consumption during steaming was 48.47% lower for MWP than CP. • Processing time and cost was reduced by approx. 7 h and 1583 INR/ton for MWP. • MWP yielded lower broken kernels, higher whiteness and showed lower cooking time. Parboiled rice (PBR) is extremely popular in South Asian nations however, the conventional process of parboiling performed for PBR production is energy and time intensive. In the present work, a unique approach of parboiling is proposed in which high moisture freshly harvested paddy was taken as the raw material for parboiling and the conventional hot water soaking (HWS) was replaced by microwave-assisted soaking (MWS). An in-depth comparative assessment was carried out between the conventional parboiling (CP) and the microwave-assisted parboiling (MWP) based on actual and theoretical energy consumption and feasibility of the MWP was ascertained given process economy and PBR qualities into account. An overall energy saving of 20.48% was achieved through MWS as compared to HWS. The specific energy consumption for steaming during MWP was found to be 78.22 kJ kg⁻¹ which is 48.47% lower as compared to the CP. Moreover, the overall processing time and cost of processing were reduced by 6.91 h and 1583 INR/ton for MWP in comparison to CP. From the quality point of view, MWP resulted in a lower broken percentage, higher grain whiteness and lower cooking time of the PBR produced.