Processing affects availability of antioxidants.

Scientists at the University of Maryland evaluated baking time and temperature to see how they affect the availability of antioxidant properties in baked pizza crust. They found that processing conditions may significantly affect the antioxidant availability of wheat-based products. It's possible to optimize processing variables to produce better functional foods with a greater level of available antioxidants.

Essentially, changing preparation techniques for pizza crust can alter its antioxidant properties. By increasing certain factors, such as baking time, the researchers were able to increase antioxidant properties. Increasing the fermentation time was also able to increase those properties. Investigators tested the effect of different fermentation times--up to 48 hours--and found antioxidant levels can increase by 100%.

Pizza crusts were prepared using the Trego and Lakin varieties of wheat. Trego is a hard white winter wheat variety developed in recent years by researchers at the Kansas Agricultural Experiment Station of Kansas State University. Lakin is a hard white wheat. Both varieties were analyzed for their total phenolic content and radical scavenging capacity against the 2, 2-diphenyl-1-picrylhydrazyl (DPPH); cation ABTS; peroxyl (oxygen radical absorbance capacity--ORAC); and hydroxyl (HOSC) radicals.

In general, increasing the degree of thermal processing increased the availability of antioxidants in the pizza crust. Increasing the baking time from 7 to 14 minutes at 400 F increased total phenolic compound (TPC) values by 20% and 13%, and DPPH and ABTS radical scavenging capacities by 38% and 33%, respectively, in the Trego and Lakin wheat varieties.

These data suggest that the specific variety of wheat may alter the effects of thermal processing on antioxidant properties. Increasing baking temperatures from 400 F to 550 F with a baking time of 7 minutes increased TPC values by 29% to 42%; and radical scavenging capacities by 44% to 45%, 12% to 34%, 13% to 33%, and 31% to 32% for DPPH, ORAC, HOSC, and 2, 2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), respectively.

Further information. Liangli Yu, Department of Nutrition and Food Science, University of Maryland-College Park, 0112 Skinner Building, College Park, MD 20742; phone: 301 405-0761; fax: 301-314-3313; email: lyu5@umd.edu.