April 21, 2005

• Scientists discover why some popcorn kernels don’t pop

  

  By Rick Callahan
  

  Associated Press
  

  Eat your way to the bottom of almost any bag
  of popcorn and there they are -- the rock-hard, jaw-rattling unpopped
  kernels known as old maids.

  The nuisance kernels have kept many a dentist busy, but their days
  could be numbered: Scientists say they now know why some popcorn
  kernels resist popping into puffy white globes.

  It’s long been known that popcorn kernels must have a precise moisture
  level in their starchy center – about 15 percent – to explode. But
  Purdue University researchers found the key to a kernel’s explosive
  success lies in the composition of its hull.

  Unpopped kernels, it turns out, have leaky hulls that prevent the
  moisture pressure buildup needed for them to pop and lack the optimal
  hull structure that allows most kernels to explode.

  “They’re sort of like little pressure vessels that explode when the
  pressure reaches a certain point,” said Bruce Hamaker, a Purdue
  professor of food chemistry. “But if too much moisture escapes, it
  loses its ability to pop and just sits there.”

  The findings may help popcorn breeders select the best varieties – or
  create new ones – with superior hulls that yield few, if any, unpopped
  kernels. But for now there’s no way to screen out potential old maids
  before they end up in bags of popcorn.

  Hamaker and his associates compared the microwave popping performance
  of 14 Indiana-grown popcorn varieties and examined the crystalline
  structure of the translucent hulls of both the popped kernels and the
  duds.

  In the varieties popped, the percentage of unpopped kernels ranged from
  4 percent in premium brands to 47 percent in the less-expensive ones.

  The findings could be good news for people who savor the snack and
  those who grow the 17 billion quarts of popcorn sold each year in the
  United States.

  Wendy Boersema Rappel, a spokeswoman for the Chicago-based Popcorn
  Board, said popcorn processors are always looking for ways to improve
  their product, including reducing the number of old maids.

  “It’s one of life’s annoyances – it’s not rocking anyone’s world, but
  our members always like to improve their product,” Rappel said.

  Hamaker said two popcorn manufacturers have already expressed interest in Purdue’s findings.

  The research, funded by Purdue’s Whistler Center for Carbohydrate
  Research, which Hamaker directs, has been published online and will
  appear in the July 11 edition of the journal BioMacromolecules.
  

  • 9:11 pm
  • 1 Comment