$re = '/^(?<amount>.*?\s*\b(?:tsp|teaspoon|packet|ounces|fl\.\s*ounces|fl\.\s*ounce|cup))\b\s*(?<val>.*)$/mi';
$str = '2 fl. ounces paprika
3/4 fl.ounce paprika
1 Chopped Tomato
1/2 Cup yogurt
unclear amount of whatever
1 packet pasta
½ tsp fine sea salt
3 sliced onions
1/2 teaspoon heavy cream
2 ounces paprika
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php