Phenolic content and antioxidant activity of linden syrup prepared from dried flowers by hot and cold brewing

Abstract

Linden flower syrup has been used as a supportive treatment for colds in folk medicine. In this study, syrup was prepared by mixing sucrose and herbal infusion made by hot (HB) and cold (CB) brewing from air-dried (AD) and freeze-dried (FD) linden flowers. The syrup was preserved by heating at 75 °C for 25 min followed by storage at 5°C for 21 d. The colour, pH, phenolic content, and antioxidant activity were determined. Hot brewing produced syrups with a significantly higher amount of phenolics, flavonoids, and antioxidant activity than cold brewing. The contents of catechin (39.59 mg/L), epicatechin (159.07 mg/L), chlorogenic acid (44.66 mg/L) and tiliroside (1.92 mg/L) contents were higher for HB-FD than those of the HB-AD samples. Regarding cold brewing, it was found to effectively extract catechin, epicatechin, and chlorogenic acid from air-dried flower samples.