Food proteins from animals and plants: Differences in the nutritional and functional properties

Animals and plants are the main sources of dietary proteins, and there are important differences in the type of protein that they supply. The differences include molecular structure, amino acid profile, digestibility, and technical functionality in food, i.e. the ability to gel, emulsify, bind water etc. These inherent differences influence their bioavailability from a human nutrition perspective, as well as the sensory quality of foods containing animal or plant proteins. These fundamental differences mean that designing plant-based foods to mimic animal foods requires much more than simple substitution of one ingredient with another. We survey some of the nutritional and technological functionality data for animal- and plant-derived food proteins and discuss the nature and implications of the differences between them. Plant-based foods typically provide less complete protein nutrition because of lower digestibility and source-specific deficiencies in essential amino acids, compared with animal proteins. Such differences may not be as essential for adults as they are for infants and young children, due to their developmental requirements. Plant proteins can be subjected to various processes to bring their functionality closer to that of animal proteins (e.g. hydrolysis to improve solubility), but some processes that improve functionality also diminish amino acid bioaccessibility or bioactivity, creating negative nutritional consequences. Much more research and innovation are required to enhance the potential of plant proteins. In the short to medium term, nutritional and functional synergies between plant and animal proteins may offer a path to creating nutritious and attractive foods.