β-Cyclodextrin-Aided Aqueous Extraction of Antioxidant Polyphenols from Peppermint (Mentha × piperita L.)

This study explored the use of β-cyclodextrin (β-CD) as an additive to improve the aqueous extraction of antioxidant polyphenols from peppermint (Mentha × piperita). For this purpose, an initial single-factor screening was performed to test the effect of β-CD concentration on the yield of polyphenol extraction. In the following step, the extraction process was optimized through response surface methodology, considering β-CD and temperature as the process variables. The experimental design included the yield in total polyphenols and total flavonoids, the ferric-reducing power and the antiradical activity as the responses. The optimization showed that each response was maximized at different levels of β-CD concentration, but in all cases, 80 °C was the optimum extraction temperature. The composition of the extracts produced was profiled by high-performance liquid chromatography (HPLC). A comparison of the β-CD extract with the aqueous and hydroethanolic extracts revealed that the addition of β-CD at a specified concentration might boost aqueous polyphenol extraction. On the other hand, the hydroethanolic extract exhibited the richest polyphenolic profile. It was also shown that the β-CD extracts might possess improved antiradical activity. It was concluded that β-CD-aided polyphenol extraction from M. piperita may provide extracts with enriched polyphenolic composition and improved antioxidant characteristics, and this technique may be considered an alternative to solvent extraction.