SunOpta Inc., a Canadian supplier of organic and specialty foods, jumped the most in seven years after hedge fund Tourbillon Capital Partners pushed the company’s board to explore a sale. Tourbillon, the largest shareholder with a 9.9 percent stake, sent a letter to SunOpta’s board on Friday urging it to “immediately engage an independent investment bank to advise on a value maximization process — including the execution of a sales process.” Tourbillon cited the company’s poor share-price performance in the past two years and said SunOpta has a “uniquely attractive business” in the rapidly growing area of sourcing hard-to-find organic and non-genetically modified ingredients. SunOpta sells a range of products from non-genetically modified soybeans to Nature’s Finest organic juice. The company last year completed its biggest-ever acquisition, purchasing frozen-fruit producer Sunrise Holdings Inc. for $444 million. The shares have tumbled by more than half since the transaction was announced. On Friday, SunOpta rose as much as 32 percent in New York, the biggest intraday gain since March 2009. The shares jumped 27 percent to $4.84 at 5:20 p.m.