Delay Posts in RSS Feeds on WordPress

<?php
function wpcode_snippet_publish_later_on_feed($where) {

    global $wpdb;

    if (is_feed()) {

        // Timestamp in WP-format
        $now = gmdate('Y-m-d H:i:s');

        // Number of units to wait
        $wait = 10; // integer

        // Choose time unit
        $unit = 'MINUTE'; // MINUTE, HOUR, DAY, WEEK, MONTH, YEAR

        // Add SQL syntax to default $where. By default 10 minutes.
        $where .= " AND TIMESTAMPDIFF($unit, $wpdb->posts.post_date_gmt, '$now') > $wait ";
    }

    return $where;
}