(a) removing at least a part of hemicellulose from lignocellulosic biomass to form hemicellulose-removed lignocellulosic biomass, wherein the lignocellulosic biomass comprises lignin, cellulose, and hemicellulose;

(b) modifying the hemicellulose-removed lignocellulosic biomass with an acid to form an acid-treated reaction mixture; and

(c) adding a base to the acid-treated reaction mixture to neutralize remaining acidic components to form a neutralized reaction mixture, followed by removing water-soluble materials from the neutralized reaction mixture to form solid particles,

wherein the solid particles obtained in step (c) contain hemicellulose-derived components formed through step (b) and step (c) in an amount of 3 wt % or less, based on the total weight of lignin-derived components, cellulose-derived components, and hemicellulose-derived components formed through step (b) and step (c).