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.
Phenylketonuria (PKU) is characterized by a person's inability to metabolize the amino acid phenylalanine.If the body can not process part of the protien phenylalanine (phe) then it can cause severe brain damage, skin disorders, behavioral problems, heart defects or even mental retardation.enetic Testing. The phenylalanine tolerance test is one form of genetic testing for PKU. It is performed by giving a person a measured amount of phenylalanine and the concentration of phenylalanine in the blood plasma is measured.