The superfood gold rush

Açaí has become a craze among health-conscious Americans

In the aisles of the American supermarket, hierarchies arise and collapse with the velocity of soap-opera drama. The produce section is especially cutthroat; here, because novel products are so rare, it’s the stories that must change to entice consumers. Back in the 1970s, the Chinese gooseberry went global — cultivated in New Zealand and shipped to the world — after being rechristened as the friendlier kiwi. Just a few years ago, kale was king, rehabbed as a luxury green after decades as a garnish and a Southern standby. Similarly, quinoa, long a staple crop in the Andes, has lately become