Philippine purple treat under threat

IN New York City, people line up outside a bakery before it opens to buy a brioche doughnut whose glaze shines a startling purple. In Paris, people sip purple-­coloured lattes with a mellow, nutty scent. In Melbourne, a purple tinge gives hot cross buns a gentle sweetness.

The common ingredient in these items is ube, or the Philippine purple yam, and the world’s new hunger for it is starting to strain the people who farm it.