Soy Protein is one of the most popular plant based alternatives, due to the fact that its essential amino acid (EAA) content is highly similar to whey protein, which makes it an especially common choice among vegans and vegetarians. However, in comparison with whey protein, soy based supplements often contain more sugar. This may be to a disadvantage to you, especially if you are on a pre-competition diet when you keep a close eye on every gram of macronutrients you put into your body. Always make sure you read the packaging labels carefully and pick the protein supplement that works the best for you and addresses your needs properly.
Soy protein is usually manufactured from white flakes that are obtained by peeling and defatting soybeans. The flakes are ground into a powdery flour that contains about 50 – 54 % of protein. Using a variety of technological processes, the flour is then filtered, cutting out aromatic compounds and sugars. This way, a concentrate with about 65 - 75 % of protein content is produced.
In some cases, this concentrate may be further processed by centrifugation, drying and removing the fibre. The resulting product of these processes is a soy isolate, which can theoretically reach up to 90 % of protein content, but in reality, the actual concentration sits usually at about 85 %. The prototypical product in this category is Protein Soy Isolate.