Impact of cooking temperature on the quality of quick cooking brown rice

Abstract

Three cooking temperatures (72, 80, and 88 °C) were applied to two rice genotypes (Puitá Inta CL and INOV CL) for preparing quick cooking brown rice. Samples were analyzed for cooking time, color, scanning electron microscopy (SEM), damaged grains, amylose, protein content and extractability, differential scanning calorimetry (DSC), X-ray diffraction (XRD), sensory properties, and in vitro digestion. Cooking time was reduced from 23.0-23.6 to 5.5-6.9 min when the highest temperature was applied, depending on genotype. The greatest grain deformation was observed for treatments from Puitá Inta CL. XRD showed greater ability of brown rice from Puitá Inta CL to gelatinize at 88 °C. Appearance, texture, and flavor of quick cooking brown rice prepared at 88 °C was inferior to its brown rice counterparts. Starch digestibility decreased by around 20-22% in 88 °C-prepared-quick cooking brown rice. Lower digestibility values were determined for 88 °C-treated-INOV CL, and were associated with grain integrity.

Keywords: Damaged rice; In vitro digestion; Instant rice; Rice cooking temperature.