Checking for key name in nested json
If the property to be checked is always belong to an item in the value
property, then you can do this way :
var isQualityExists = content["value"].Any(v => ((JObject)v).Properties() .Any(p => p.Name.Contains("quality")) );
Otherwise, you may want to create a function that recursively check for a specific property name existence all over the JObject
.