Store peeled onions in the freezer. Chop your onions and place them in a flat layer on a cookie sheet and freeze. After they are frozen, remove the onions from the sheet and store them in Ziploc bags or storage containers in the freezer. One of the down sides of this option is limited storage space.hop your onions and place them in a flat layer on a cookie sheet and freeze. After they are frozen, remove the onions from the sheet and store them in Ziploc bags or storage containers in the freezer. One of the down sides of this option is limited storage space.
Newborns with phenylketonuria initially don't have any symptoms. Without treatment, babies usually develop signs of PKU within a few months. PKU symptoms can be mild or severe and may include: 1  Intellectual disability (formerly called mental retardation). 2  Delayed development. 3  Behavioral, emotional and social problems.
Causes and symptoms. PKU symptoms are caused by alterations or mutations in the genetic code for the PAH enzyme. Mutations in the PAH gene prevent the liver from producing adequate levels of the PAH enzyme needed to break down phenylalanine. The PAH gene and its PKU mutations are found on chromosome 12 in the human genome.