diff --git a/src/Format/MixedFormat.php b/src/Format/MixedFormat.php
index 6026e91..3101929 100644
--- a/src/Format/MixedFormat.php
+++ b/src/Format/MixedFormat.php
@@ -30,7 +30,7 @@ class MixedFormat implements IFormat
             return $this->response->withBody(new Stream('[object]'));
         }
         if (is_array($result)) {
-            return $this->response->withContentType(ContentType::JSON)->withBody(new Stream(json_encode($result, JSON_UNESCAPED_UNICODE)));
+            return $this->response->withBody(new Stream(json_encode($result, JSON_UNESCAPED_UNICODE)));
         } else {
             return $this->response->withBody(new Stream((string)$result));
         }