The old school of thought said that a desert tortoise should not be fed fruit more than 10% of his diet. I don't know if that has changed over the years, but I still abide by the rule of basically no fruit for desert type tortoises. That means Russians, Sulcata and the Western U.S. desert tortoises. I don't know about the other Mediterranean tortoises. Why don't you save the fruit such as bananas for a sometimes treat?
The reason for this rule (again, hearsay, not first hand knowledge) is that too much fruit (sugar) might cause a parasite bloom in a tortoise-system that is designed for weeds and grasses. However, I'll bet that a desert tortoise that comes upon a Prickly Pear cactus that has just dropped all its fruit won't stop at just one.