Evaluation of mint (Mentha spicata) hydrodistillation aqueous byproducts and its utilization in development of bioactive-rich functional drink

Abstract

Distillation aqueous byproducts are discarded despite being rich in bioactive components. In this study, the aqueous byproducts (hydrolats and flask water fractions) resulting from the hydrodistillation of fresh and dry mint leaves were compared, with a primary focus on their essential oil yield and bioactive properties. Dry mint leaves yielded approximately eight times more essential oil than fresh leaves. The hydrolat extracted from dried mint leaves (MHD) exhibited higher phenolics (35.5 ± 1.1d mg GAE/100 mL), flavonoids (7.8 ± 0.29d mg QE/100 mL) and 2,2-diphenylpicrylhydrazyl scavenging potential (21.13%), compared to the hydrolat derived from fresh leaves (MHF), which had lower values (7.115 ± 0.9e mg GAE/100 mL, 5.72 ± 0.422d mg QE/100 mL and 6.79%, respectively). Similarly, the flask water fraction from dry mint leaves (FWF2) had a higher concentration of bioactive compounds compared to that from fresh leaves (FWF1). The hydrolat with higher bioactivity (MHD) was selected for infusion to develop a flavored drink and its GCMS profile indicated a relatively abundant presence of D-Carvone. The flavored drink prepared with a 20:100 ratio of hydrolat was preferred for its flavor intensity, a key sensory parameter for determining the hydrolat amount. Additionally, for Gum Arabic, a 2.5:100 ratio in the drink resulted in a more acceptable consistency score.