This paper reports the hemicellulose content in three rice straw types (OM5451, IR50404, and 6976 commons from An Giang province, Vietnam). Alkaline extraction assisted with ultrasound was employed. In this process, samples were mixed with 2 M sodium hydroxide and ultrasonicated for 30 min at 90oC. Then, the mixture was continuously heated at 90oC and stirred at 40 rpm for 1.5 h...