@Article{jrm.2022.022594, AUTHOR = {Yaoguo Liu, Yao Chen, Huifang Liu, Wei Chen, Zhiwei Lei, Chiyu Ma, Jie Yin, Wen Yang}, TITLE = {Controlled-Release of Plant Volatiles: New Composite Materials of Porous Carbon-Citral and Their Fungicidal Activity against Exobasidium vexans}, JOURNAL = {Journal of Renewable Materials}, VOLUME = {11}, YEAR = {2023}, NUMBER = {2}, PAGES = {811--823}, URL = {http://www.techscience.com/jrm/v11n2/49897}, ISSN = {2164-6341}, ABSTRACT = {Citral (Eo) exhibits excellent fungicidal activities. However, it is difficult to maintain long-term fungicidal activity due to its strong volatility. Herein, a controlled-release strategy by using biomass-derived porous carbon (BC) was developed to overcome the drawback of Eo. New composite materials were prepared by loading Eo on tea stem porous carbon (BC@Eo), and their controlled-release fungicidal activity against Exobasidium vexans was assessed. BC with a large specific surface area of 1001.6 m2/g and mesoporous structure was fabricated through carbonization temperature of 700°C. The BC@Eo materials were characterized using Fourier-transform infrared spectroscopy and X-ray powder diffraction. The results suggested that chemical and physical interactions occurred in BC@Eo. The Eo release profile suggested a biphasic pattern with an initial fast release on days 1–14 and a subsequent controlled phase on days 14–30. The in vitro cumulative release percentage of Eo from BC@Eo was 51% during one month, and this result was significantly lower than that from free Eo (cumulative release percentage of Eo of 82% in one week). The antifungal activities of Eo and BC@Eo against E. vexans were determined using the inhibition zone method. The results indicated that Eo and BC@Eo formed large inhibition zones of 19.66 ± 0.79 and 21.92 ± 0.77 mm, respectively. The influence on the hyphal structure of E. vexans was observed by scanning electron microscopy on day 30. The hyphal structure of E. vexans treated with BC@Eo was more shrunken than that treated with Eo at 30 days, suggesting that BC@Eo prolongs the fungicidal activity against E. vexans. This study demonstrated that the encapsulation of Eo in BC for developing the BC@Eo materials could be a promising strategy to inhibit volatility and maintain the fungicidal activity of Eo and provide a potential alternative for the reuse of abundant tea biomass waste resources.}, DOI = {10.32604/jrm.2022.022594} }