Primary walls are the major textural component of plant-derived foods. The ripening of fruits and vegetables is associated with changes in wall structrue and composition. Plant-derived beverages often contain significant amounts of wall polysaccharides. Some wall polysaccharides bind heavy metals, stimulate the immune system or regulate serum cholesterol. Wall polysaccharides are used commercially as gums. gels, and stabilizers. Thus, cell wall structure and organization is of interest to the plant scientist, the food processing industry and the nutritionist.