Combined effects of glucose oxidase, papain and xylanase on browning inhibition and characteristics of fresh whole wheat dough

• An enzymatic browning inhibitor for fresh whole wheat dough is developed.
• Glucose oxidase decreases carotenoids while increases elastic and viscous modulus.
• Xylanase reduces phenolic content while decreases elastic and viscous modulus.
• Papain eliminates polyphenol oxidase while decrease elastic and viscous modulus.
• Optimal bioenhancer inhibits the browning and improves the rheological properties.

In this study, a glucose oxidase (GOX), papain and xylanase combination was developed for fresh whole wheat dough for both browning inhibition and rheological improvement. Measurements of carotenoids extracted from enzyme-treated doughs showed that 0.001% (w/w) GOX could catalyze the oxidization of 40.0% carotenoids and thus cause a decrease of browning index (BI) by 5.20 during dough preparation. For 24 h browning inhibition, 0.010% (w/w) xylanase and papain individuals were able to separately act on the phenolic compounds and polyphenol oxidase, leading to lower BI rises (5.36 and 7.04, respectively) of doughs as compared to the BI rise (13.53) of the control dough; however, 0.020% GOX caused a higher BI rise (16.60) than control although it made BI decrease by 6.34 at 0 h. Rheological investigations on enzyme-treated doughs revealed that both xylanase and papain led to decreases of elastic (G′) and viscous modulus (G″) of doughs while GOX caused increases of G′ and G″. Therefore, an optimal combination composed of 0.010% (w/w) xylanase, 0.005% (w/w) papain and 0.002% (w/w) GOX was carried out using orthogonal experimental design by comparing BI rises in 24 h, which was also proved as a rheological improver for fresh whole wheat dough.