It sounds like you may be overcooking the zucchini.

If you're using a large zucchini, cut it in half lengthwise and scrape out the seeds. If small, you can skip it. Cut the zucchini in thin threads or ribbons - a vegetable peeler works well for ribbons. Bring a pot of water to a boil and put the cut zucchini in a sieve. Dip into the boiling water only until it softens slightly. Drain and add sauce.

Karen