Onion peeling is the processing step that removes dry outer skins from onion bulbs, typically using compressed air or mechanical rollers after topping and tailing, and it is the standard first stage for frozen, dried and fresh-cut onion production.
In trade practice
After topping and tailing, bulbs pass through a compressed-air peeling tunnel where high-velocity air strips the papery outer layers without wetting the flesh, which helps preserve pungency and reduces microbial load on the peeled surface. Operatives on an inspection belt remove remaining skin patches, double skins and defective bulbs before the product moves to cutting or slicing. For dehydrated onion, thorough peeling is critical because residual skin causes dark specks in the finished powder. A common quality issue is incomplete peeling of small-diameter bulbs, which may require a secondary manual pass.
In a specification
A specification for peeled onion or onion-derived products typically states a maximum permitted level of skin-on pieces and may require that peeled bulbs be free from green cores and double skins above a defined size.