uses
  SysUtils,DBXJSON;

type
  TProcessJSONString = TProc<TJSONString>;

procedure DoJSONObject(o: TJSONObject; Process: TProcessJSONString); forward;

procedure DoJSONArray(o: TJSONArray; Process: TProcessJSONString);
var i: integer;
    v: TJSONValue;
begin
  for i := 0 to o.Size - 1 do begin
    v := o.Get(i);
    if v is TJSONObject then
      DoJSONObject(v as TJSONObject,Process);
  end;
end;

procedure DoJSONObject(o: TJSONObject; Process: TProcessJSONString);
var i: integer;
    p: TJSONPair;
begin
  for i := 0 to o.Size - 1 do begin
    p := o.Get(i);
    Process(p.JsonString);
    if p.JsonValue is TJSONObject then
      DoJSONObject(p.JsonValue as TJSONObject,Process)
    else if p.JsonValue is TJSONArray then
      DoJSONArray(p.JsonValue as TJSONArray,Process)
    else if p.JsonValue is TJSONString then
      Process(p.JsonValue as TJSONString);
  end;
end;

var o: TJSONObject;
begin
  o := TJSONObject.ParseJSONValue('{"data":{"results":[{"Branch":"ACCT590003"}]}}') as TJSONObject;
  try
    DoJSONObject(o,procedure (o: TJSONString)
      begin
        WriteLn(o.ToString);
      end
    );
  finally
    o.Free;
  end;
  ReadLn;
end.