New Class of Compounds for Inhibiting Enzymatic Browning of Food Products

Technology #12693

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Maurice R. Marshall Jr
Kurt Frederick Schulbach
Managed By
John Byatt
Assistant Director 352-392-8929
Patent Protection
US Patent 8,563,061
PCT Patent Application WO 2009/131996


Appearance and color are important attributes to consumers when selecting and buying fresh foods. However, many fresh food items (e.g. shrimp and fruit) contain enzymes that will produce “browning” of the food over a relatively short period of time. This color change not only adversely affects the visual appeal of the food item, but may also negatively affect flavor and nutritional value. A number of products are currently used to prevent enzymatic browning, but can also cause problems themselves. Sulfites are commonly used by the food industry, but these also can produce a severe allergic reaction in some consumers. Other additives acidify the food, which can lead to other problems. For these reasons, additional compounds that can be used in food preparation are required. Researchers at the University of Florida have discovered a novel compound in extracts of mussels that effectively inhibits browning of food. Hypotaurine and related compounds appear to be a safe and effective alternative to a number of potentially problematic anti-browning agents currently used in food.


Added to fresh foods (e.g. fruit, shrimp) and drinks (e.g. apple juice, wine) to prevent enzymatic browning


  • Naturally occurring compound found in some food items
  • Could replace allergy-causing sulfites in some foods providing a unique competitive advantage
  • Provides longer lasting protection from enzymatic browning in comparison to citric acid or ascorbic acid, allowing for longer lasting food for market sale and consumption


The enzymatic browning caused by polyphenol oxidase (PPO) is a major cause of quality loss in fruits and vegetables. Polyphenol oxidase is a copper-containing enzyme that catalyzes the oxidation of o-diphenols to o-quinones, which can further react to form colored pigments. Sulfites and related compounds are powerful inhibitors of enzymatic browning, but their use is limited since they can produce adverse reactions in a significant proportion of the population. Safe and effective alternatives to sulfites could be very useful to the food processing industry. The various chemicals that have been shown to inhibit enzymatic browning can be divided into two major classes: those that act on the enzyme and those that act on the products. In the latter group, acidification with citric acid is commonly used to reduce enzyme activity, or ascorbic acid is used to react with the polyphenols and reduce them to colorless compounds. However, such approaches may only temporarily inhibit enzymatic browning. Thus, use of compounds that inhibit PPO activity is preferable. Potent inhibitors of PPO were discovered in extracts of blue mussels (Mytilus edulis). Characterization of this inhibitory activity resulted in the discovery that hypotaurine is a potent anti-browning agent that may be of value to the food industry.