The disclosed inventions include microalgal biomass high in protein and fiber, wherein the biomass has been manufactured through heterotrophic fermentation. The materials provided herein are useful for the manufacture of meat substitutes and meat enhancers, as well as other food products that benefit from the addition of digestible protein and dietary fiber. Structural properties of foods are enhanced through the use of such materials, including texture and water retention properties. High in protein and fiber food materials of the invention can be manufactured from edible and inedible heterotrophic fermentation feedstocks, including corn starch, sugar cane, glycerol, and depolymerized cellulose.