diff --git a/lib/html2rss/config.rb b/lib/html2rss/config.rb
index 813a628..c40e07d 100644
--- a/lib/html2rss/config.rb
+++ b/lib/html2rss/config.rb
@@ -43,12 +43,16 @@ def headers
       global_config.fetch('headers', {})
     end
 
-    def options(name)
+    def attribute_options(name)
       feed_config.dig('selectors').fetch(name, {}).merge('channel' => channel_config)
     end
 
+    def attribute?(name)
+      attribute_names.include?(name.to_s)
+    end
+
     def categories
-      feed_config.dig('selectors').fetch('categories', [])
+      feed_config.dig('selectors').fetch('categories', []).map(&:to_sym)
     end
 
     def selector(name)
@@ -56,9 +60,9 @@ def selector(name)
     end
 
     def attribute_names
-      attribute_names = feed_config.fetch('selectors', {}).keys.map(&:to_s)
-      attribute_names.delete('items')
-      attribute_names
+      @attribute_names ||= feed_config.fetch('selectors', {}).keys.map(&:to_s).tap do |attrs|
+        attrs.delete('items')
+      end
     end
 
     private
diff --git a/lib/html2rss/item.rb b/lib/html2rss/item.rb
index b5fe358..bce5ac8 100644
--- a/lib/html2rss/item.rb
+++ b/lib/html2rss/item.rb
@@ -15,17 +15,18 @@ def initialize(xml, config)
     private_class_method :new
 
     def respond_to_missing?(method_name, _include_private = false)
-      config.attribute_names.include?(method_name) || super
+      config.attribute?(method_name) || super
     end
 
     def method_missing(method_name, *_args)
-      attribute_config = config.options(method_name.to_s)
-      return super unless attribute_config
+      return super unless respond_to_missing?(method_name)
 
-      extractor = ItemExtractors.get_extractor(attribute_config['extractor'])
-      value = extractor.new(xml, attribute_config).get
+      attribute_options = config.attribute_options(method_name)
 
-      post_process(value, attribute_config.fetch('post_process', false))
+      extractor = ItemExtractors.get_extractor(attribute_options['extractor'])
+      value = extractor.new(xml, attribute_options).get
+
+      post_process(value, attribute_options.fetch('post_process', false))
     end
 
     def available_attributes
@@ -33,8 +34,12 @@ def available_attributes
         @config.attribute_names) - ['categories']
     end
 
+    ##
+    # At least a title or a description is required to be a valid RSS 2.0 item.
     def valid?
-      [title.to_s, description.to_s].join('') != ''
+      title = self.title if config.attribute?(:title)
+      description = self.description if config.attribute?(:description)
+      [title, description].join != ''
     end
 
     ##
diff --git a/spec/html2rss_spec.rb b/spec/html2rss_spec.rb
index 4c471bf..3fc1834 100644
--- a/spec/html2rss_spec.rb
+++ b/spec/html2rss_spec.rb
@@ -130,10 +130,10 @@
       end
 
       describe 'item.category' do
-        subject(:categories) { item.css('category').map(&:text) }
+        subject(:categories) { item.css('category').to_s }
 
         it 'sets the author as category' do
-          expect(categories).to include 'manni'
+          expect(categories).to include '<category>manni</category>'
         end
       end