o:30968 Physicochemical characterisation of Thymus serpyllum extracts prepared using natural deep eutectic solvents en ABSTRACT Thymus serpyllum L. (wild thyme) extracts were prepared using 1 g of plant material and three natural deep eutectic solvents (30 mL, malic acid+maltose, lactic acid+menthol, or citric acid+glycerol with 50% of water) in maceration (90 min). The extracts were characterized in terms of total polyphenol content (TPC), total protein content, extraction yield, zeta potential, conductivity, pH, density, surface tension, and viscosity. TPC was the highest in citric acid+glycerol extract (35.06±1.13 mg gallic acid equivalents (GAE)/g of plant material), whereas malic acid+maltose and lactic acid+menthol extracts possessed similar TPC (29.62±1.11 and 28.94±1.15 mg GAE/g, respectively). Total protein content amounted to 5.55±0.20 mg/g in citric acid+glycerol extract, while significantly lower values were determined in malic acid+maltose and lactic acid+menthol extracts (1.22±0.30 and 1.73±0.18 mg/g, respectively). The extraction yield was the highest for citric acid+glycerol extract, 1.57±0.11%, followed by malic acid+maltose and lactic acid+menthol extracts, 1.28±0.10 and 1.27±0.13%, respectively. Zeta potential (absolute value, as a predictor of potential application in water treatment) was low in all extracts (0.86±0.06 mV for citric acid+glycerol, -0.35±0.09 mV for lactic acid+menthol, and -0.17±0.05 mV for malic acid+maltose extract). The conductivity (as a predictor of antioxidant capacity) was in the range of 2.35±0.21 and 2.71±0.29 mS/cm (citric acid+glycerol and malic acid+maltose extracts) to 5.70±0.23 mS/cm (lactic acid+menthol extract). pH ranged from 1.44 in citric acid+glycerol extract to 1.78 and 1.85 in malic acid+maltose and lactic acid+menthol extracts. Density varied from 1.067±0.003 g/mL for lactic acid+menthol extract to 1.169±0.002 and 1.195±0.005 g/mL for citric acid+glycerol and malic acid+maltose extracts. Surface tension was the highest in citric acid+glycerol extract (38.0±0.4 mN/m), followed by malic acid+maltose and lactic acid+menthol extracts (31.5±0.4 and 25.9±0.1 mN/m, respectively). The viscosity of lactic acid+menthol extract was significantly lower (1.83±0.30 mPa•s) in comparison to malic acid+maltose and citric acid+glycerol extracts (6.64±0.15 and 7.84±0.10 mPa•s, respectively). The highest TPC, total proteins, and extraction yield were measured in citric acid+glycerol extract, while lactic acid+menthol extract possessed the highest conductivity and the lowest density, surface tension, and viscosity. Therefore, the constitution of natural deep eutectic solvent should be optimized depending on the future application of T. serpyllum extract. Natural deep eutectic solvent, polyphenols, Thymus serpyllum, physical properties 1552100 978-99955-81-45-9 2023-10-02T11:16:40.430Z 44 yes 46 Milena Milošević University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Serbia Aleksandar Marinković University of Belgrade, Faculty of Technology and Metallurgy, Serbia person Petar Batinić University of Belgrade, Faculty of Technology and Metallurgy, Serbia person Ivan Đuričković University of Belgrade, Faculty of Technology and Metallurgy, Serbia person Aleksandra A. Jovanović University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor tehnoloških nauka person 0000-0001-5394-0125 application/pdf 489024 https://phaidrabg.bg.ac.rs/o:30968 no yes 1 70 92000004 11A24 11A41 11A29 Engineering, environment and materials in process industry-Proceedings 258 University of East Sarajevo Faculty of Technology 2023