The controversial move, which has some people questioning Innocent's claims to be ethical, amounts to between 10 and 20% of the company.
In a statement, the three founders of Innocent, who still run the company and are celebrating 10 years of the firm this month, attempted to allay customers' fears by saying the deal would help Innocent learn from the market leaders, as well as helping them "get innocent out to more places".
Co-founder Richard Reed said: "The three of us who set up the business will continue to run and manage Innocent. We will be the same people making the same products in the same way."
He added that everything Innocent stands for, including the push for better quality, the use of more socially and environmentally conscious ingredients and to support charities in the countries where their fruit comes from, still stood.
He said: "In fact, this deal will simply allow us to do more of these things."
In 2007, Innocent came under fire from some quarters when it struck a deal which saw McDonald's sample Innocent Smoothies in a range of Happy Meals.
United Kingdom
Innocent sells minority stake to Coca-Cola
LONDON - Innocent, the ethical, healthy smoothie brand, has sold a £30m stake in its company to fizzy drinks giant Coca-Cola in a move that its owners say will help finance European expansion.