Here are two smoothie recipes using silken tofu. I haven't tried either one but I'm sure they're good. They're both from _The Teen's Vegetarian Cookbook_.
To make this one IBS-safe, I would use mangoes or peaches instead of any of the berries, and soy milk instead of any of the juices.
Berry Breakfast Shake
5 ice cubes 1 cup frozen or fresh mixed berries 1 ripe banana 1/2 cup silken tofu (to make this shake extra creamy and to give protein) 3/4 cup orange juice or soy milk
1. Crush the ice cubes in a blender. 2. Add berries and "pulse" the blender until berries are pureed. Add remaining ingredients and puree until smooth. Makes one big shake. Variations: Experiment with different kinds of fruits (try mangoes, blueberries, peaches, or strawberries) and juices (pineapple and apple are good).
This one should be fine as written.
Orange Wake-up Smoothie
5 ice cubes 3 tablespoons frozen orange juice concentrate 1 banana 1/2 cup soy milk 1/4 cup pineapple juice (or use extra soy milk instead) 2 tablespoons silken tofu (optional, but it adds creaminess)
1. Crush the ice cubes in a blender. 2. Add remaining ingredients and blend until creamy. Makes one big smoothie.