Xylanase cleave non-starch polysaccharides (NSP) releasing xylosylic moieties with reducing ends. The reducing moieties are oxidized in an alkaline milieu by forming orange-yellow compounds with the 2-hydroxy-3,5-dinitrobenzoic acid (dinitro salicylic acid). These yellow compounds are measured at a wavelength of 530 nm and the released reducing ends are quantified with a validated Ronozyme WX standard