The discovery comes from work by researchers at the University of California, Davis, commissioned by the Washington Tree Fruit Research Commission.

Apple trees produce a sugar alcohol, sorbitol, starch and sucrose in their leaves, which is transported from the leaves to the developing fruit. Researchers investigated how sorbitol distribution in trees affects fruit quality by using apple trees that had been genetically modified to produce less of the enzyme necessary for synthesizing sorbitol. The transgenic apples accumulated more than twice the glucose, but less fructose, starch and malic acid.

“We also found that there were no unfavorable effects on fruit firmness or appearance associated with the altered sorbitol-to-sucrose ratio,” said Abhaya Dandekar, a plant science professor and lead researcher on the study. “What was unexpected in the apples from the transgenic trees was their low starch, low acidity and higher soluble solids content."

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