Oxido-reductases and lipases as dough-bleaching agents

To replace benzoyl peroxide as a bread dough-bleaching agent, pure and commercial oxido-reductases (peroxidases, catalases, glucose oxidases, lipoxygenase, and laccase) were screened based on degradation of beta-carotene in a liquid system (5 mu g of beta-carotene/mL of 0.1M citrate phosphate buffer at pH 5.5 or 6.5) or dough. Peroxidases had the best bleaching activity; some catalases also showed bleaching potential in a liquid system but not in bread dough, suggesting that screening enzymes in liquid media has limited application for dough. In 100 g of flour, combinations of peroxidase (3,000 U), lipase (815-1,630 U), and linoleic acid (0-300 mg) completely bleached bread dough.