The reddening of dyer's saffron florets induced by a fungal glucose oxidase

Abstract

Summary Glucose oxidase (EC 1.1.3.4) from Aspergillus niger was fed to the triturated florets of dyer's saffron ( Carthamus tinctorius ) and the bathochromic colour change was investigated with or without addition of glucose. Glucose oxidase could change bright-orange florets to reddish-orange when incubated in floret paste even with no addition of glucose. Upon addition of D-glucose to the reaction medium at the 555.6 mM level, the oxidase activity was enhanced by about 2-fold that where no glucose was added. l-glucose also promoted the enzyme reaction, but only to a lesser extent ( D -form/ L -form = 1.7: 1.0).