"Look, if you take days to process, the fruit is not OK anymore," Monteiro said. "You need to process the fruit in 24 hours."
On the edge of the rainforest, Monteiro has built his processing plant, one of several sleek new acai factories in the area. His plant, Bony Acai, recently was inspected and approved by the U.S. Food and Drug Administration.
Monteiro said he had to work with engineers to develop the machinery for processing acai on a mass scale to meet world demand. "We feel here like industrial revolution here," said Monteiro. "We take the manual process, the knowledge from that people, join that people with the engineer and its happened."
Monteiro said production was growing rapidly. "I think we double every year," he said.
Bony Acai produces half-a-million dollars' worth of acai concentrate a week. Much of it now headed to the U.S. market.
On the outskirts of Belem, "Nightline" visited one of the smaller new processing plants, called Top Acai. The proprietor, Herbert Levy, joined the acai explosion when he saw his kids drinking it in Rio. He believes it's better than gold for the people of the region.
"It's much better because the gold it's only a few people who make money with gold," said Levy. "You don't have poor people who make money with gold. It's very tough. Here, you have the owner of the acai. It's not us. The owner of the acai is the people who are in the jungle of the Amazon."
But is the "purple gold" really fool's gold? According to scientists, the juice has the same healthy properties as other dark fruits, like blueberries, blackberries and red grapes. All are good for you, but -- like acai -- only as part of healthy diet with regular exercise.
"The bottom line with acai is that it is a fruit, it's not a drug," said Steve Talcott, the Texas A&M professor. "You shouldn't consume it as a drug. You shouldn't expect a drug-like effect."
Talcott believes Americans are going to see a lot more acai in our lives.
"You're going to see new forms of acai," he said. "You're going to see it in beverages. You're going to see in cosmetics. You're going to see it in more dietary supplements, you're going to see it in your shampoo. We are going to be drinking it and pouring it on your body.
"If you think it's crazy now from a marketing perspective, I think we've just seen the tip of the iceberg," he added.
Back in the Amazon, producers worry that the confusion in the U.S. market is going to give acai a bad name before people can understand how good it can be.
Herbert Levy invited us to taste some acai fresh off his production line. The fruit is so bland that it is usually mixed with juice from a sweeter fruit, but he prefers it with just a little sugar added.
Soon enough, we will all get a chance to see -- and taste -- for ourselves.