Volatile signatures and antioxidant potentials of white mugwort (Artemisia lactiflora) extracts in emulsions: The influence of pH on functionality and stability

Abstract

Background: White mugwort (Artemisia lactiflora), a medicinal plant native to several Asian countries, is known for its antioxidant-rich compounds and aromatic volatiles, making it a promising natural additive in food and cosmetic emulsions. However, its stability and effectiveness can be influenced by environmental factors, especially pH.

Objective: This study investigated the volatile compound composition and antioxidant efficiency of white mugwort in its fresh and dried forms under different pH conditions (3, 5, and 7), with the aim of exploring its potential as a natural antioxidant in oil-in-water (O/W) emulsions.

Methods: Volatile compounds were analyzed using GC-MS. The antioxidant efficiency of white mugwort extract was evaluated in O/W emulsions at different concentrations (200, 400, and 600 ppm) and compared with BHT and α-tocopherol (both at 200 ppm) using peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) assays.

Results: Volatile compounds were analyzed by GC-MS, identifying 31 compounds in fresh samples and 34 in dried samples. Drying at 50 °C for 24 hours caused reductions in several key volatiles, including β-Myrcene, β-cis-Ocimene, 3-Carene, and γ-Gurjunene. Conversely, compounds such as Santolina triene, Caryophyllene, and Bicyclosesquiphellandrene increased, indicating thermal degradation and chemical conversion during drying. pH significantly influenced the volatile profiles. These findings highlight the role of pH-driven chemical reactions in aroma stability. The antioxidant study showed that antioxidant efficiency increased with higher extract concentrations. Extracts at pH 3 and 5 demonstrated stronger antioxidant activity than those at pH 7, evidenced by longer lag times in lipid hydroperoxide formation and lower TBARS values. This pH-dependent behavior was not observed with BHT or α-tocopherol, suggesting a unique interaction between white mugwort phenolics and the emulsion interface.

Novelty: This study provides novel insights into the volatile compound dynamics and antioxidant properties of white mugwort under varying processing and environmental conditions, with a particular focus on pH- and dose-dependent antioxidant performance in emulsions. These findings hold significant scientific and industrial relevance.

Conclusion: Overall, white mugwort extract demonstrated promising potential as a natural antioxidant, especially under mildly acidic conditions, with superior performance to α-tocopherol and applicability in clean-label formulations. Additionally, insights into pH effects on volatile stability contribute to improving aroma retention in food and cosmetic products.

Keywords: Aromatic, Medicinal plant, Natural antioxidant, Oil-in-water emulsion