This study presents for the first time results on structure feature, basic physical properties, torrefaction treatment, adsorption property, component content and antimicrobial properties of the cork back from Quercus variabilis. The cork back consisted of numerous white stone cell bundles with a dense and firm texture and irregularly shaped cells exhibiting considerable deformation and wrinkles. The cork back had the average density of 0.37 g/cm3, average hardness of 91.60 HA and the average thickness was 31.44 % of the total cork thickness. The average colorimetric parameters values of L*, a*, and b* of the cork back were 21.92, 2.34, and 6.42, respectively. Increasing torrefaction temperature increased the quality loss of the cork back, decreased energy yield and volatile matter content, and increased ash and fixed carbon content. With the elevation of fixed carbon, the higher calorific value of the cork back also increased. Following high-temperature torrefaction at 300 °C, the higher calorific value of cork back was 24.00 MJ/kg which increased by 30.29 % compared to untreated cork back. The cork back powder had significant adsorption performance for methylene blue and the maximum adsorption capacity could reach 511.61 mg/g. Compared with cork,the cork back had a high content of lignin and polysaccharides, with a suberin content of only 4.07 %. The total extractives content in cork back was 7.49 %. The water extractives of the cork back exhibited the most significant inhibitory effect on Escherichia coli, with the lowest inhibitory concentration recorded at 2 mg/mL. This research offers essential data for the processing and utilization of the cork back, which contributes to enhance the utilizing efficiency of cork resources.
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