Flour, water, baking powder, salt and oil represent roughly 95% of the finished product weight of a flour tortilla. Each major ingredient plays a primary function in the quality.
- Flour provides the structure, shape, and matrix of the tortilla.
- Water turns the flour proteins into gluten and activates the functionality of the rest of the ingredients. For example, baking powder will not provide a leavening effect unless enough water is available.
- Oil provides lubrication and flexibility.
- Baking powder generates leavening.
- Salt provides flavor and strengthens the gluten.
Although you can produce tortillas with just those 5 major ingredients, it is not recommended beyond home kitchens. Tortilla made with only flour, water, oil, baking powder, and salt will be soft and pliable for several hours after production. But, if they aren't consumed immediately they will start drying out, loosing flexibility, and becoming sticky within 24 hours. By 48 hours post-production mold growth will be visible on the surface.
Obviously this is not good for industrial production so minor ingredients that make up about 2% of the formulation are needed to help extend tortilla shelf-life and prevent staling and molding.
Staling is prevented when emulsifiers are added
These minor ingredients maintain the water linked to the oil phase so the tortilla will remain moist and flexible for much longer. Some common emulsifiers are mono and diglycerides, Datem esters, etc.
Molding is prevented when ingredients that reduce water activity are added. Natural or artificial preservatives or mold inhibitors like sodium & calcium propionate, potassium sorbate, fumaric acid, etc. can be used for this function.
A balanced formula of major ingredients that provide basic structure and functionality and minor ingredients that extend the shelf-life is the key for a successful tortilla product.