What is Soy Protein?

Soy protein is a plant protein that comes from the soybean (sometimes referred to as a soya bean). The protein isolate from soybeans is made from soybean meal that has been defatted and dehulled.  Soy protein isolate is a popular choice for vegans, vegetarians and anyone who wants to eliminate or reduce animal proteins (including dairy) in their diet.

How Much Protein is in Soy?

Soy protein isolate has a protein content of around 90% (moisture free) and is commonly used to make plant-based protein powders. Soy protein powders are typically used to aid muscle maintenance and muscle growth and are a popular supplement in a vegan diet.

Dehulled and defatted soya beans are also processed into two other kinds of high protein products, soy flour (50% protein), and soy concentrates (70% protein).

Popular soy protein food sources include Soy Milk, Tofu, Miso, Edamame and Soy Protein Powders.

Is Soy Protein a Complete Protein?

Whilst many plant-based proteins are not complete proteins, soy protein is a complete protein as it contains all of the essential amino acids for human nutrition.

Soybean products are a good source of protein for vegans and vegetarians because they offer a complete protein profile. Soy protein food products can be a good alternative for animal based foods, and they are often chosen as a meat substitute, they also typically contain less saturated fats that animal meats.

A Serving of mature raw Soybeans contains all 9 essential amino acids:

  • Tryptophan
  • Threonine
  • Isoleucine 
  • Leucine 
  • Lysine 
  • Methionine
  • Phenylalanine
  • Valine 
  • Histidine

Soybean Nutrition and Protein

A 3.5oz serving (100g) of raw soybeans supplies around 36% protein, 30% of carbs and 446 calories. A serving of 100g of soy bean isolate contains around 90% protein, whereas Soy flour contains around 50% protein and soy concentrates contain around 70% of protein.

Soybeans contain an abundance of nutrients, a 100g serving or raw soybeans contain the following daily values (DV) including dietary fibre (37%), protein (36%), and have high mineral contents including manganese (120%), iron (121%), they are also high in folate and several B vitamins.

Nutritional Information for 100g of Raw Mature Soybeans:

  • Calories: 446 
  • Protein: 36.5 grams
  • Carbs: 30 grams
  • Fiber: 9.3 grams
  • Fat: 19.94 grams

Soybean Protein Food Sources

Soybeans can be eaten whole or made into a variety of food products, including Tofu, Miso, Natto, Tempeh, Edamame, Soy Milk, Soy Sauce and other dairy and meat alternatives, Soya bean isolate in the form of soy protein powders can be added to plant-based smoothies and shakes.

Examples of Soybean foods high in protein.


Tofu is a popular food source for vegan and vegetarian diets and contain around 8g of protein per 100g serving. Tofu (also known as soybean curd) is made by coagulating soya bean milk and the curds are pressed in solid white blocks. There are plenty of Tofu recipes to choose from to help boost your plant protein intake.


Tempeh originally came from Indonesia and is made by cooking soybeans that are then fermented to create patties. A 100g serving of Tempeh contains around 20g worth of protein, and is a popular choice in vegan diets. Tempeh can be incorporated in to many vegan recipes and dishes, with exotic dishes including Vegan Beijing Tempeh to Vegan Chickpea Tempeh.

meat alternatives

Soybean Meat Alternatives – there has been a rise in the demand of soya bean meat alternative food sources that imitate animal meats, such as hot dogs, soybean burgers and sausages. They are an excellent source of plant proteins for vegan diets and they typically contain less saturated fat than animal meat.

Soybean Milk

Soy milk is a popular alternative to dairy milk and is an excellent choice for people who are lactose intolerant or who follow a vegan diet. 1 Cup of Soymilk contains around 6.95 grams of protein, compared with one cup of cow’s milk which contains around 7.69g of protein. The protein content of Soya milk is higher than most other plant based milks such as almond milk, which contains around 1.55g of protein per cup, nutritional information for Soy Milk.


  • Soy bean protein is a good source of plant protein for vegetarian and vegan diets, or those who want to reduce the amount of meat they eat.
  • Soya beans are one of the few plant proteins that contain all 9 essential amino acids.
  • Not only does soy provide high levels of protein, they are also a good source of nutrients.
  • There are a wide range of food products that contain soy protein including Tofu and Tempeh, and soy protein powders can be easily used as an ingredient in shakes and smoothies.

Related Information

Is Soy Protein Good or Bad?

What are the best plant based proteins for vegans

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