Biochemical characterization and fuel properties of endemic taurus flowering ash (Fraxinus ornus subsp. cilicica) bark from Turkey

• Published in: Processes 2023-09, Vol.11 (9), p.1-19
• Main Authors: Şen, Ali Umut, Simões, Rita, Yücedağ, Cengiz, Miranda, Isabel M., Sofia Feitor Fernandes, Ângela, Pereira, Helena
• Format: Article
• Language: English
• Subjects: Additives; Antioxidant; Antioxidants; Bark; Burnout; Calcium; Calcium compounds; Chemical composition; Diterpenes; Endemic species; Ethanol; Fatty acids; Flavonoids; Flowering; Fraxinus ornus; Functional materials; Hydrophilicity; Hydroxy acids; Ignition temperature; Lignin; Lignocellulose; Lipophilic; Lipophilicity; Phenolic compounds; Plant extracts; Polyphenols; Polysaccharides; Scientific imaging; Suberin; Thermal degradation
• ISSN: 2227-9717; 2227-9717
• DOI: 10.3390/pr11092774

Taurus flowering ash (Fraxinus ornus subsp. cilicica) is an endemic tree species in Turkey. The bark of the species was characterized for summative chemical composition, the monomeric composition of polysaccharides, phenolic content, in vitro and ex vivo antioxidant properties of hydrophilic extracts, the composition of lipophilic extractives and suberin, and thermal degradation. The bark has an elevated ash content (17%), primarily composed of calcium, and a noteworthy extractive content (38.9%), predominantly of hydrophilic compounds. The antioxidant activity of the bark extracts is moderate, with an IC50 value of 40 g/mL and an EC50 value of 230 g/mL by DPPH and TBARS methods. The lipophilic extractives principally contain fatty acids and diterpenoids. The suberin content is low (1%) and composed primarily of !-hydroxy acids with 9,10,18 trihydroxyoctadecanoic acid as the major suberin monomer. The lignin content is low (9.8%), and polysaccharides represent 33%. The ignition temperature of the bark is 190 C, the burnout temperature is 653 C, and the activation energy in combustion is 29 kJ mol1. A biorefinery concept was developed considering the bark’s chemical and thermal characteristics to convert approximately 90% of the bark mass into valuable chemicals, extracts, functional materials, and additives. This work has been supported by FCT–Fundação para a Ciência e Tecnologia within the R&D Unit Forest Research Centre, CEF (UIDB/00239/2020) and also from the FCT/MCTES (PIDDAC) national funds to CIMO (UIDB/00690/2020 and UIDP/00690/2020) and SusTEC (LA/P/0007/2021). U. ¸Sen acknowledges support from FCT through research contracts (DL 57/2016), R. Simões by a Ph.D. scholarship (PD/BD/128259/2016), and Â. Fernandes by the national funding by FCT and P.I. in the form of institutional scientific employment program.