Scientist Ron Buttery, left, watches as Gary Takeoka, a research chemist with the U.S. Department of Agriculture, prepares to extract the volatiles in black olives to understand the quality and compare it to that of domestic and non-domestic olives. The USDA teamed up with experts at UC Davis to investigate the various flavor profiles of domestic and imported olives. Lacy Atkins/San Francisco Chronicle photo

Don Olson of the U.S. Department of Agriculture uses ultraviolet light on mushrooms to increase their nutritional value. Lacy Atkins/San Francisco Chronicle photo

Ron Buttery identified a compound that enhances flavor. Lacy Atkins/San Francisco Chronicle photo