Custom subtitle inside shop loop

add_action ('woocommerce_product_options_general_product_data', 'subtitle_product_data_metabox');
function subtitle_product_data_metabox() {
   echo '<div class="options_group">';
   woocommerce_wp_text_input (array (
      'id'                => 'product_subtitle_inside_loop',
      'value'             => get_post_meta (get_the_ID(), 'product_subtitle_inside_loop', true),
      'label'             => 'Product subtitle',
      'description'       => 'Subtitle text to appear between title and price'
  ));
   echo '</div>';
}

add_action ('woocommerce_process_product_meta', 'save_subtitle_field_on_update', 10, 2);
function save_subtitle_field_on_update ($id, $post) {
      update_post_meta ($id, 'product_subtitle_inside_loop', $_POST['product_subtitle_inside_loop']);
}

add_action( 'woocommerce_after_shop_loop_item_title', 'show_subtitle_after_shop_loop_item_title', 1, 0 );
function show_subtitle_after_shop_loop_item_title() {
    global $product;
    $product_subtitle_inside_loop = $product->get_meta ('product_subtitle_inside_loop');
    echo $product_subtitle_inside_loop;
}