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Oxido-Reductases and Lipases as Dough-Bleaching Agents

¹Food Research and Development Centre, Agriculture and Agri-Food Canada, 3600 Casavant Blvd. West, St. Hyacinthe, Quebec, Canada J2S 8E3. ²Corresponding author. Phone: 450/773-1105; Fax: 450/773-8461; E-mail: gelinasp@em.agr.ca ³The Governor's Foundation, Food Research and Development Centre, St. Hyacinthe, Quebec, Canada.

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 β-carotene in a liquid system (5 μg of β-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.