摘要
Abstract
Ultrasound-assisted extraction(UAE)coupled with response surface methodology(RSM)was applied to optimize the recovery of polyphenols from spent coffee grounds(SCGs),a typical by-product of the coffee industry.Extraction temperature,time,and liquid-to-solid ratio were investigated as major variables.The optimal conditions are determined to be 49 ℃,25 min,and a liquid-to-solid ratio of 29∶1(mL/g).Under these conditions,the total polyphenol yield reaches 16.71 mg GAE/g DW,which closely matches the predicted value of 16.75 mg GAE/g DW,thereby verifying the accuracy of the model.Antioxidant activity was evaluated by DPPH and PTIO radical scavenging assays.At a volume fraction of 4％,the UAE extract shows a DPPH scavenging rate of 99.38％,which is higher than that of the water extract.In the PTIO assay,the UAE extract shows a scavenging rate of 27.86％at a volume fraction of 80％,whereas the water extract reaches 36.19％at 100％.Moreover,ultra-high-performance liquid chromatography-mass spectrometry(UHPLC-MS)identifies chlorogenic acid,ellagic acid,and protocatechuic acid as the major phenolic compounds,confirming the chemical basis of the antioxidant effect.These findings demonstrate that UAE not only enhances the extraction efficiency of polyphenols from SCGs but also yields extracts with strong antioxidant activity.The study provides technical support and scientific evidence for the valorization of coffee by-products as natural antioxidants,highlighting their potential application in skincare formulations and daily chemical products.关键词
咖啡渣/超声辅助提取/多酚/响应面优化/抗氧化活性Key words
spent coffee grounds/ultrasound-assisted extraction/polyphenols/response surface optimization/antioxidant activity分类
化学化工
