CAMBRIDGE, MASS. — Culture Pop Soda, a functional, probiotic soda brand, has raised $21 million in a Series B funding round led by Enlighten Hospitality with additional investments from former Starbucks chief executive officer, Howard Schultz. The four-year-old soda brand formulates its sodas from juice, spices and a live probiotic. “It’s a really clean ingredient list,” said Tom First, CEO and founder of Culture Pop Soda. “They’re a refreshing soda with no sweeteners, no stevia, and no sugar other than the fruit juice. ”First has had his hand in the beverage space since the founding of his first company Nantucket Nectars Juice Co. in 1989. Not only has First founded several beverage brands, he also has sat on boards of other brands like Essentia Water and OWater, and was a managing partner at First Beverage Group.