Abstract:Using Tartary buckwheat grains as the research object, D-chiro-inositol (DCI) was extracted via an enzyme-assisted ultrasonic method. The effects of pH, enzymatic hydrolysis temperature, enzymatic hydrolysis time, enzyme concentration, solid-liquid ratio, and ethanol concentration on DCI concentration were investigated, and the extraction process of DCI was optimized using response surface methodology. The optimal enzymatic hydrolysis pH was 6, enzymatic hydrolysis temperature was 36.4 ℃, enzymatic hydrolysis time was 0.5 h, enzyme concentration was 2.1%, solid-liquid ratio was 1:10, and ethanol concentration was 48%; as such, DCI concentration measured under these conditions was 5.87 mmol/L. Further, the in vitro hypoglycemic activity of the extract before and after purification was evaluated using α-amylase and α-glucosidase. DCI was purified with activate carbon and a solid-phase extraction cartridge. Anion (SAX) solid-phase extraction cartridge produced the best purification effect, increasing the purity by 80%. The 50% inhibitory concentration (IC50) of DCI on α-glucosidase in Tartary buckwheat decreased from 0.675 to 0.472 mg/mL, indicating a significant purification effect. The proposed α-galactosidase-assisted ultrasound method effectively produced a high concentration of DCI, and the purified DCI showed excellent in vitro hypoglycemic activity. These findings provide a theoretical reference for the comprehensive development and utilization of Tartary buckwheat.
