Natural deep eutectic solvent as tool for improving Rosa canina L. polyphenol recovery in maceration

Abstract

Rosa canina L. extracts were prepared using water or three natural deep eutectic solvents (NADESs: betaine+malic acid, betaine+sucrose, and citric acid+sucrose with 50% of water) and maceration. The extracts were characterized in terms of total polyphenol content (TPC), ABTS radical scavenging potential, extraction yield, zeta potential, conductivity, pH, density, surface tension, and viscosity. TPC was the highest in betaine+malic acid extract (10.4 mg gallic acid equivalents, GAE/g), and the lowest in water and citric acid+sucrose extracts (6.5 and 6.4 mg GAE/g, respectively). ABTS radical scavenging potential was the highest in water extract, 5.6 mmol Trolox/g, whereas the lowest was in citric acid+sucrose extract, 2.6 mmol Trolox/g. Extraction yield was the lowest for betaine+malic acid extract, 0.607 %, and statistically significantly higher for betaine+sucrose extract, 1.22 %. Zeta potential (absolute value) was the highest for betaine+sucrose extract (-2.12 mV), and the lowest for citric acid+sucrose extract (0.29 mV). Conductivity was in the range of 0.25 mS/cm (betaine+sucrose extract) to 5.46 mS/cm (betaine+malic acid extract). pH ranged from 3.0 in betaine+malic acid extract to 4.5 in water and betaine+sucrose extracts. Density varied from 1.00 g/mL for water extract to 1.19 g/mL for betaine+sucrose extract, while surface tension varied from 35.0 mN/m for betaine+sucrose extract to 40.6 mN/m for water extract. Viscosity of water extract was 1.52 mPa·s and it was significantly higher for citric acid+sucrose extract, 10.67 mPa·s. The application of NADESs as an extraction medium can improve polyphenol recovery from rose hips, as well as extraction yield and conductivity, but depending on NADES composition. Namely, the highest TPC and conductivity were measured in betaine+malic acid extract, while betaine+sucrose extract possesses the highest extraction yield. Thus, the constitution of NADES should be optimized depending on the future application of the extract.