The effect of extrusion puffing on the physicochemical properties of brown rice used for saccharification and Chinese rice wine fermentation

Abstract

Chinese rice wine (CRW), with its high nutritional value and unique flavor, has been popular in China for thousands of years. The traditional steps of immersion and steam cooking during the brewing of rice wine have several drawbacks, including the long production time, large energy consumption, generation of wastewater and the large production area it occupies. Extrusion puffing has the potential to overcome these drawbacks. In this study, the physicochemical properties of extruded-puffed brown rice obtained under different conditions were analyzed. The puffed extrudates exhibited low bulk density, high water solubility index and higher surface area than the steam-cooked brown rice. Extrusion puffing operates at high temperatures, high pressure and provides mechanical shearing forces, resulting in the puffed extrudates having a higher degree of gelatinization, as determined by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR) and differential scanning calorimetry (DSC), revealed the disruption of the native crystalline structure. The effect of extrusion on enzymatic hydrolysis was evaluated using amylase digestion. The results indicated that puffed extrudates significantly improved the enzymatic hydrolysis rate and yield. Moreover, the catalytic efficiency was evaluated by kinetic constants, with extrusion puffing treatment demonstrating an efficiency18-fold higher than steam-cooked brown rice. Finally, extruded-puffed blown rice was used for Chinese rice wine fermentation. The extruded-puffed blown rice improved alcohol yield during the fermentation process, which increased the wine yield by 12.4% compared to traditional cooking methods.