NEW YORK ( TheStreet) -- John Sculley, the former chief executive officer of Apple  (AAPL) and Pepsi  (PEP), is now investing in several private companies he says are potentially game-changing and could go public or be acquired by public companies in the future. 

Sculley recently wrote the book Moonshot!, which examines strategies executives can use to build transformative businesses.

One of Sculley's investments is in Zeta Interactive, a firm he co-founded with his friend David Steinberg. Sculley said Zeta Interactive is one of the largest big data marketing analytic companies in the world. The company is based in New York City and has 700 employees. 

"We grew about 100% top line, we're very profitable, and we're well-positioned to go public, probably in 2016," he said.

Another company Sculley is involved with is MDLIVE, a telehealth firm that connects patients with doctors via phone or Internet video. The service operates around the clock and is designed to handle non-emergency situations.

"This is a company that I think has the potential to become a unicorn, meaning more than a billion-dollar valuation," Sculley said. He added that MDLIVE has a close partnership with Walgreens  (WAG) and has also worked with more than 800 hospitals to provide telehealth services.

"If you think back to 20 years ago with online banking, people said, 'Oh, I wonder if that's really gonna work, will people really trust it?'" Sculley said. "Well, they're saying the same things about telehealth today."  

Sculley is also chairman of a company in Florida called PDQ, a casual dining chain that was created by the founders of Outback Steakhouse  (BLMN). Sculley said PDQ will be a public company someday. "We're just having incredible success with very nutritious foods, no red meats, remember these are the Outback Steakhouse guys, now it's all chicken," he said. "Everything is fresh, every day."

Sculley added PDQ is just one more example of providing people with a great customer experience and giving them that experience at a disruptive price point. "It's amazing how fast these businesses will grow," he said.

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