Effects of the hot air roasting process on brown rice moisturized by water-spraying method

The hard texture of brown rice, attributed to its bran layer, poses significant challenges in improving its palatability. This study investigated the effects of hot-air roasting on the morphological characteristics, thermal properties, and water absorption of brown rice, moisturized using a water-spraying method to enhance texture. Moisture-controlled roasting resulted in a significant difference in the L* values, with the highest observed at 20 % water content. The extent of cracking and fine fissure formation varied with roasting temperature, resulting in increased water absorption. These structural changes subsequently influenced the tan δ value, hardness, and stickiness in the rheological analysis post-cooking. The gelatinization degree significantly increased with higher roasting temperatures and retrogradation effects were noted at 130 °C and 150 °C with a 15 % water content during cooking. Texture and sensory evaluations confirmed an increase in hardness as retrogradation progressed. The observed changes in this study have a profound impact on the textural and sensory attributes of the final cooked product.