The composition, physicochemical properties, antimicrobial and antioxidant activity of wood vinegar prepared by pyrolysis of Eucommia ulmoides Oliver branches under different refining methods and storage conditions

Abstract

To enhance the quality of wood vinegar (WV), the WV prepared by pyrolyzing Eucommia ulmoides Oliver (EUO) branches at the temperature of 650 °C were refined by using different physicochemical methods. The crude WV was refined by ultra-low freezing and thawing (WVFT), charcoal adsorption (WVCA), and activated carbon adsorption (WVACA), respectively. Meanwhile, the chemical compositions, antimicrobial and antioxidant activity of the crude WV (WVC), the WV (WVS) prepared two years ago, and the photolysis WV (WVP) were investigated. The results showed that the WVFT obtained by ultra-low freezing and thawing method possessed better quality with pH of 3.45, density of 1.045 g/cm³ , refractive index of 26.85% and total organic acid of 11.00%. It was also found that WVFT had better inhibition rate of 83.33% against Bacterium prodigiosum, indication the excellent antibacterial activity. Moreover, WVFT had significant effect on scavenging rate (98.72%) for hydroxyl radicals. This research could offer some references for the refining methods of WV, and the WV was expected to be a potential candidate for materials of antioxidant and antimicrobial.