Using fractional factorial designs with mixture constraints to improve nutritional value and sensory properties of processed food

Recipes in cookbooks are presented as a list of directions describing how to cook fixed amounts of ingredients to prepare pleasurable food. Similarly, industrial food products can be considered as processed mixtures of ingredients for which process parameters and mixture parameters should be investigated simultaneously when trying to improve their nutritional and sensorial properties. This work proposes a simple, generic and efficient approach to combine process and mixture factors in the same design by handling easily any mixture constraint in the frame of fractional factorial designs. The approach has been successfully applied in many situations and is illustrated through a case study to improve an all-family cereal recipe both in terms of nutritional value (i.e. 50% sugar reduction and partial replacement of refined wheat flour by whole grains) and sensory properties.