Intensification and Monitoring by Raman Spectroscopy of Parboiling Process

Although parboiling is dependent on a hydration step, knowledge of the paddy rice characteristics during this stage is lacking. This study aimed to identify changes in the morphological structure of starch during hydration, as well as the elementary chemical composition of the grain. In addition, water absorption kinetics was adjusted and simulated by mathematical models. Concentration gradient, temperature, and physical properties of paddy rice influenced mass transfer during hydration. Certain hydrothermal conditions promoted an irreversible disorganization in molecules of starch (crystalline structure to amorphous), which characterized its gelatinization and the parboiling of paddy rice. The hydrothermal conditions altered the intensity of excitation of the chemical groups identified, what suggests the Raman technique as a potential method of monitoring moisture. The application of this information reduces costs of industrial processes. Furthermore, mathematical modeling can also be used as a process control tool, reducing the need for experimental tests. Practical applications This study allowed the characterization of moisture transfer in the hydration stage of paddy rice parboiling process. From the collected data, it was possible to affirm that parboiling of paddy rice takes place during hydration when the right conditions are use. Then, there would be no need for later steps, reducing costs for the industries and providing the process intensification. In addition, the Raman technique is suggested as a possible alternative method for moisture monitoring and mathematical modeling as a tool for process optimization, since it is able to predict and simulate water gain in the hydration step, eliminating the need for experimental tests.