The thicker and denser the fruit, the creamier the sorbet will be. If the sorbet is made using peaches, pineapples, or bananas, the sorbet will be thick and creamy. If the sorbet is made using less dense fruits like watermelon, raspberries, or grapefruit, the result will be less creamy and icier in texture. For more details, check out this post from Serious Eats.