The firms did not disclose the financial terms of the deal, but a source told Reuters that the business was valued at A$185m ($172.5m).
Retail Zoo, which owns the Boost Juice Bars chain, currently operates 294 stores in Australia and a further 100 in other countries including Singapore and the UK.
Riverside acquired a 65 per cent stake in Retail Zoo for A$64m in 2010.
Retail Zoo’s founders are expected to retain a minority stake in the company.
Boost Juice Bars’s UK business is backed by the Business Growth Fund, which made a £2.5 investment in January 2013.
The company was launched in Adelaide in 2003 and then expanded into more than 20 other markets.
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