Avocados are processed in a controlled manner to optimize and maintain their levels of mannoheptulose and perseitol. The avocado flesh is used as a source of these materials in food compositions, especially pet foods. The process claimed comprises the following steps: A. ) harvesting the unripe fruit having a hardness greater than about 5 LBF; B. ) contacting the fruit from step (A) with ethylene gas until the fruit exhibits a penetrometer reading greater than about 2 LBF and less than about 5 LBF, according to the Penetrometer Test Procedure; and C. ) terminating step (B) by a procedure selected from removing the avocados from contact with the ethylene gas, or cooling the avocados to a temperature at or below about 45[deg.]F, or both, to provide an avocado product.