Novel Insights Into the Recovery and Stabilization of Rosmarinus officinalis Volatile Aroma Compounds Using Green Solvents

Abstract

In this study, the integrated application of supercritical CO2 and natural deep eutectic solvents (NADES) was investigated in order to establish a green procedure that enables obtaining and stabilizing the aroma volatile constituents of Rosmarinus officinalis L. Supercritical CO2 was used to obtain rosemary extracts that possessed an abundance of terpenes, particularly monoterpenes 68.97–88.08% and sesquiterpenes 5.38–21.22%. The obtained extracts were further dispersed in different NADES (betaine/glycerol (Bet/Gly), betaine/ethylene glycol (Bet/EG), and betaine/glycerol/sucrose/water (Bet/Gly/Suc/W) and their stability was assessed at room temperature. The headspace profile of the samples and their antioxidant activity were monitored for 6 months. Changes in the chemical profile of the extract were detected, which corresponded to terpene transformation reactions. In the control (CO2 extract), the development of non-terpene components such as acetic acid was detected, which make the product unsuitable for use. Conversely, the accumulation of acetic acid was not observed in the NADES samples. The antioxidant activity of the control was the most significantly decreased during 6 months, while among the NADES samples, the reduction of activity occurred only in Bet/Gly sample. In Bet/EG and Bet/Gly/Suc/W samples, activity remained the same during the same period. The results suggest that the NADES could serve as stabilization media for CO2-extracted rosemary volatile components. Furthermore, this represents a simple, green process of obtaining readily applicable products with extended stability at room temperature.