PHP find keywords in XML feed - preg_match_all - php

Question

I'm loading in a rss feed in XML. I am then attempting to search the RSS feed for keywords. I then need to it email myself with a notification that it found these key words and their contents.
Example i have:
$keywords = "iphone|ipad|ipod";
$rss = simplexml_load_file("http://myfeed.com/news?format=xml");
foreach ($rss->entry as $i)
{
//need to check the title tag for the keywords
//email myself a notification with the keywords found
}
UPDATE
Ok i have the following which is part working:
function getPartsWithRegex($text, $regex){
preg_match_all($regex, $text, $array);
return $array[0];
}
$keywords = "LLC|socks";
$rss = simplexml_load_file("http://feeds.myfeed.com/iphoneapps-news?format=xml");
$text = "Downcast - Jamawkinaw Enterprises LLC";
$regex = "/$keywords/i";
foreach ($rss->entry as $i)
{
$title = (string)$i->title;
$productNumbers = getPartsWithRegex($text, $regex);
}
if(count($productNumbers) > 0){
foreach($productNumbers as $productNumber){
echo $productNumber . '<br />';
}
}
else {
echo "Nothing found.";
}
This works when i pass $productNumbers = getPartsWithRegex($text, $regex); However, when i pass $title which has the value of $i->title it doesnt work. Even though when i echo out the value of $title to the browser it renders as: Downcast - Jamawkinaw Enterprises LLC
So to clarify when i manually enter and pass a string it works correct. However, when i pass the value from the XML which is read it doesnt. I've tried converting to string but that doesnt work.
Any ideas why?