Multiple responses optimization of antioxidative components extracted from distiller's grains using response surface methodology and identify their chemical compositions

Abstract

Distiller's grains are a waste product in the Baijiu brewing that contains many bioactive ingredients. However, few studies on the active ingredients and biological in distillers' grains. Therefore, it is promising to study the utilization of bioactive substances in distiller's grains. In our present study, an ultrasonic-assisted method was applied to extract antioxidative components from distiller's grains. Four factors: ethanol concentration, liquid–solid ratio, extraction temperature, and ultrasonic power were selected, and multiple responses were studied using response surface methodology (RSM). The effects of factors and the correlation between all responses (flavonoids content, DPPH assay, OH- assay) were investigated. The regression model indicated that all factors have significant effects on all responses. The model predicted a flavonoid yield of 6.53 mg/g, DPPH-RSC of 90.00%, and OH-RSC of 55.03% at an ethanol concentration of 69%, a liquid–solid ratio of 35 ml/g, an extraction temperature of 61℃, and a power of 300 W. The confirmation test showed the closeness of the predicted results with those of experimental values. The distiller's grains was separated by LH20 glucan gel, and total flavonoid content of 79.4% was obtained. LC-HRMS analyzed the compounds, and 24 compounds, including 7 flavonoids, were identified successfully.