Joanne, here is a recipe that I think was posted here not long ago.
I haven't tried it but it sounds reliable.
I think you can find the ingredients at a health store.Hope this is what you're looking for.

Here is the recipe:

Dough Enhancer

The ginger makes the yeast act more swiftly, the ascorbic acid strengthens the gluten, and the lecithin aids the oil in causing the strands of gluten to slip against each other more easily and thus rise better.

1 cup Lecithin granules
1 tbsp Vitamin C powder
1 tbsp Ginger, ground

Mix all ingredients and store in tightly closed glass jar. Add to breadmaker in amount EQUAL to yeast with other dry ingredients. Start machine.

Note: I think the equal means if you are using 1 teaspoon of yeast then you should use 1 t of the enhancer.
Hope this will help

And any way I'm sure you'll get more feed back on this subject, this sight is really great, with a lot of helpfull people.

Happy baking :)