The Inside Scoop on Soy Protein

The soybean is one of a large family of plants called legumes. Legumes tend to be higher in protein than other plant foods - in fact, the mature soybean is about 42% protein, 33% carbohydrate, 20% oil, and 5% hull.

Protein Power
From Soy Bean to Soy Shake
Soy Flour
Soy Protein Concentrates
Isolated Soy Protein
The Facts About Phytochemicals
The Solae™ Difference
Learn About Labels

Protein Power
Even among other legumes, the soybean stands apart. Both mature and green soybeans are often considered protein powerhouses. Just compare the grams of protein in one-half cup of green or mature soybeans to the same size serving of several familiar plant foods, including other legumes like pinto, lima, and kidney beans, blackeyed peas, and English peas.

Not only does the soybean contain more protein than other plants, the protein it contains is of higher quality. Plus, the soybean is the only plant source of protein considered a "complete protein", meaning that it not only provides all the essential amino acids your body must get from food, but these essential amino acids are also in the right balance to meet human needs.

From Soy Bean to Soy Shake
For many Westerners, eating soybeans or even traditional soyfoods regularly would mean drastic changes in their eating habits. Fortunately, today's soy protein ingredients allow people to get all the benefits of soy - in a wide variety of favorite foods like soy "burgers," drinks and shake mixes, soy protein bars and more.

How do you put a soybean into a shake? Well, all these soyfoods contain soy protein ingredients, which include soy flour, soy protein concentrates, and isolated soy protein.

Here's how soybeans are processed to manufacture soy protein ingredients:

When mature soybeans arrive in processing plants, damaged beans and any foreign material are first removed. The beans are then cracked to remove the hulls. The remaining soy chips are made into flakes - these flakes still retain the oil found in the soybean.

Soy Flour
Full-fat or natural soy flour, which is about 40% protein (based on dry weight), is made by grinding the full-fat soy flakes into a powder. Or, the fat is extracted from full-fat flakes to yield soybean oil and defatted soy flakes. Defatted soy flakes are the starting materials for making the three primary soy ingredients: soy flour, soy protein concentrate and isolated soy protein.

Defatted soy flour is then made by simply grinding defatted soy flakes to the consistency of a fine powder. At 50% protein (based on dry weight), defatted soy flour is the least refined of the three primary soy protein ingredients.

Soy Protein Concentrates
Soy protein concentrates, which are 70% protein (based on dry weight), are made from defatted soy flakes that have had most of the sugars removed but have kept much of the soy fiber. Soy protein concentrate is lower in carbohydrate than soy flour.

Processing of soy protein can have effects on retention of bioactive components. Sugar can be removed from soy flakes in two different ways. The most common method uses alcohol, the other uses water.

When alcohol is used to remove the sugar, the solvent must first be removed before making soy protein concentrate. As you will soon see, the use of alcohol extraction in the manufacture of soy protein concentrate is an important issue. Alcohol processing not only removes sugars from defatted soy flakes, it also removes valuable alcohol-soluble phytochemicals that naturally occur in soy, including the isoflavones.

However, when water is used to remove the sugars from the flakes, there is a good retention of the naturally occurring phytochemicals in the final prodcut. After the sugar is removed by the water washing process, the mixture is then dried to make the final product. Excessive water washing can also reduce the levels of many phytochemicals naturally present in soy.

Isolated Soy Protein
At 90% protein (based on dry weight), isolated soy protein is the most concentrated form of soy protein. Most isolated soy protein is manufactured using water to extract sugar from defatted soy flakes. The protein is then precipitated and dried.

Here again, excessive processing can wash away some of the phytochemicals that were originally present in the soybean. Protein Technologies International has pioneered special methods for processing isolated soy protein - methods that successfully retain the healthy phytochemicals that naturally occur in soy.

Here's more good news about isolated soy protein: it boasts a Protein Digestibility - Corrected Amino Acid Score (PDCAAS)of 1.0 - the highest possible score.

What does this mean? PDCAAS is a method for evaluating the quality of a food protein by comparing its amino acid content to the amino acid requirements of a 2 to 5 year old child. The amino acid requirements of this age group are the most demanding of any age, with the exception of infants. PDCAAS has now been adopted by the FDA for calculating the percent Daily Value of protein on food labels for adults and children over one year of age.

The Facts About Phytochemicals
There are thousands of phytochemicals, or "plant chemicals" present in plants. The type of processing used to manufacture soy protein ingredients is getting a lot of attention lately because of the impact that processing has on the bioactive phytochemicals found in soy. Alcohol processing or extensive water washing can remove substantial amounts of these substances - and that raises attention because a number of these phytochemicals are under study for their potential health benefits.

Recent research has evaluated soy protein and its naturally occurring health components including isofavones--genistein, daidzein, and glycitein. This research has focused on the impact of soy protein consumption on serious health issues like cardiovascular disease, certain cancers, bone health and menopausal symptoms.

The Solae™ Difference
The processing methods used to manufacture soy protein concentrates and isolated soy protein are very important - and different.

The alcohol-extraction method removes naturally-occurring isoflavones and other alcohol-soluble health promoting components found in soy protein. Excessive water-extraction can also reduce the amounts of these isoflavones and other substances naturally present in soy.

To preserve as much of the potentially healthy components that naturally occur in soy, DPT pioneered carefully controlled methods of processing that retain these valuable phytochemicals in Solae™ isolated soy protein. When Solae™ is made, DPT uses an innovative water-based method to remove most of the sugar from the soy flakes. Once the protein is precipitated and dried, the resulting Solae™ isolated soy protein is actually about 92% protein (based on dry weight).

Learn About Labels
To make sure you're getting soy protein and naturally occurring bioactive components in your soy-based foods, read labels carefully. Be sure to choose products made with ingredients that still retain these substances.

Check to see if the product contains isolated soy protein. If you see Solae™ brand Isolated Soy Protein from Protein Technologies International on the label you can be sure that you're getting soy protein with naturally occurring bioactive components. Don't forget to compare the fat and calories as well to be sure you're getting the most protein with the least amount of fat and calories.