Mary Tuck, who works at Dalgety Food Technology Center, sought suitable experimental designs for bread testing.
Bread is basically a mixture of flours with other ingredients.
Only so many loaves can be baked in the same oven and there are typically large variations between ovens. Thus mixture designs with orthogonal blocking properties became highly desirable. Orthogonal designs for four mixture components can be constructed by using Latin squares of side 4, with D-optimal designs having points on the edges of the mixture tetrahedron. Extensions to five factors and to the general case were also explored.