polyphenols

This study analyzes the polyphenolic composition and antioxidant activity of spent coffee ground (SCG) extracts obtained by ultrasonic extraction and maceration. It was found that SCG contains significant amounts of phenolic compounds and flavonoids. Ultrasonic extraction proved to be more effective. The results confirm the potential of SCG as a natural source of antioxidants for the food, pharmaceutical, and cosmetic industries. Moreover, the use of ultrasound significantly reduced the extraction time and increased the yield of bioactive compounds.

The Box-Behnken design was used to investigate the effect of three independent variables – time, temperature and solvent-to-solid ratio on the responses of total phenolics, total flavonoids, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and cupric ion reducing antioxidant capacity (CUPRAC) of date fruit methanolic extracts. Response surface analysis showed that the optimal ultrasound extraction parameters that maximized the responses were 30 min, 298 K and 74.4 ml/g. Under optimum conditions, UHPLC-DAD-MS/MS was used to tentatively characterize 11 phenolic compounds.