Properties of rice straw extract after subcritical water treatment.
Rice straw was separated into four parts: the upper, middle, and lower parts of the stem, and the leaf. They were treated with subcritical water at 140 to 260 °C. The yield, carbohydrate, protein, and phenolic contents were obtained as well as the UV-Vis absorption spectra and the radical scavenging activity of the extracts. The extracts obtained from the stem parts had almost the same characteristics and were different from those of the leaf part. The extracts, prepared at higher temperature, exhibited higher radical scavenging ability. The radical scavenging ability and the phenolic content showed a correlation (R2=0.92), suggesting that the phenolic substances in the extract cause its antioxidant ability.
Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
Boonnakhom
B
Tangkhavanich
Takashi
T
Kobayashi
Shuji
S
Adachi
D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification*; D002241:Carbohydrates / Q000302:isolation & purification; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification*; D005609:Free Radicals / Q000037:antagonists & inhibitors; D006358:Hot Temperature; D059625:Liquid-Liquid Extraction; D012275:Oryza / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D010940:Plant Proteins / Q000302:isolation & purification; D018547:Plant Stems / Q000737:chemistry; D014867:Water
D000975:Antioxidants; D002241:Carbohydrates; D016166:Free Radical Scavengers; D005609:Free Radicals; D010636:Phenols; D010936:Plant Extracts; D010940:Plant Proteins; D014867:Water