Protein Ingredients can be divided into animal protein ingredients and plant protein ingredients based on the protein source. Animal protein ingredients contain dairy proteins (including whey protein isolate (WPI), whey protein concentrates, casein, milk protein concentrate etc.), egg proteins and gelatin. Plant protein ingredients contain soy protein (including soy protein isolate (SPI), soy protein concentrate (SPC) and textured soy protein (TSP)), wheat protein, pea protein and other protein.