Written by: Amanda GolebiewskiDisruptive Ingredients – Soy Protein
As a meat-loving vegetarian, I’ve become very familiar with meat analog. I’ve tried meatless crumbles, chick’n nuggets, meat-free sausages, burgers, and more throughout the years. Most commonly, soy protein, soy protein concentrate, soy protein isolate, and texturized soy protein are one of the first components listed on the product’s ingredient declaration. There were so many names for this one plant. Additionally, I’ve heard rumors such as soy is bad for men, it’s bad for your heart, and it can cause hormone issues so I started looking for more clarification.
History
Originally, soy protein had other uses. It was first developed in the early 20th century by an organic chemist named Percy Lavon Julian. He isolated an industrial-grade soy protein called alpha protein which is still used today for paper coatings. Eventually, scientists began using it in U.S. Navy as a fire-fighting foam. It was able to smother flammable oils aboard ships and was released by planes. By 1959, the first food-grade soy protein isolate was invented in Chicago, IL by Central Soya. Since then soy protein has been used in almost every branch of the food industry such as meat analogs, cheeses, plant-based protein powders, breads, etc.
Processing
Unlike edamame, soy protein concentrate is made through the processing of mature soybeans. It first begins with harvesting, selecting, and cleaning the beans. Next, they are dehulled and the oil is removed through wet or dry milling. Once the oil is extracted, the defatted matter is left which can be used as soy flour or soybean meal. The defatted matter can then be further processed into protein concentrate or protein isolate. Soy protein concentrate is when the soluble carbohydrates are removed through alcohol extraction. This leaves the matter to be 65-67% protein. Soluble carbohydrate extraction is important because it results in a higher protein concentration while making the product also more digestible. Soy protein isolate is when soluble and insoluble carbohydrates are removed by taking advantage of protein’s pH and isoelectric point. Isolate is the purest form of soy protein. Another common version of soy protein listed on an ingredient declaration is texturized soy protein. Usually found in meat analogs, texturized soy protein is made by extruding the soy protein concentrate with hot, moist, and high-pressure conditions. This causes the concentrate to turn into a thermoplastic state which creates a more meat-like texture.
Uses
Soy protein can be used as the primary or supplementary protein source in both meat/non-meat food products. It can be added to aid with the product’s nutritional content, solubility, water absorption, viscosity, emulsification, and texture as well. For example, soy protein is commonly added to fortify cereals because it is a good source of the amino acid, lysine. It helps give the cereal a more balanced nutritional profile. Soy protein is a useful emulsifier; it’s water binding capabilities can enhance characteristics such as moistness without altering the food product’s texture. In other situations, it can help enhance the product’s texture by giving it a thicker mouthfeel. It can help the soy-based drink feel more satisfying and comparable to a milk-based drink.
Nutrition/Health
Soy protein is very versatile. There are many advantages to including soy protein into your diet. It is a complete protein which means all nine essential amino acids (isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine) are bioavailable. The degree of bioavailability is used to measure the amount a substance is absorbed into the body’s circulatory system and has some effect. Soy protein has a comparable amount of protein to milk, beef, and eggs. Studies have shown that both soy protein concentrate and soy protein isolate can be digested easily. It’s protein digestibility corrected amino acid score(PDCAAS) is 0.99 and 0.92 respectively. Beef’s PDCAAS score is 0.92. Another pro is soy protein can be a healthy substitution to milk. It is lactose-free so it can be used as a protein source for those who are lactose-intolerant. It can also be a good option for those with high cholesterol as soy contains very little. Soy protein is very low in saturated fat which may help reduce your risk of heart disease. Soy is rich in fiber, polyunsaturated fats, omega-3 fatty acids, B-vitamins, iron, zinc, calcium, and vitamin D.
On the other hand, there has been negative news about soy/soy protein as well. Soy has a high concentration of the plant’s version of the hormone, estrogen, called phytoestrogen. It is an isoflavone that acts as both an estrogen-agonist and estrogen-antagonist. In other words, it can bind to estrogen receptors in the human body and cause estrogenic or anti-estrogenic activity. Although it has been found that soy isoflavones have a much weaker affect when compared to human estrogen, people’s fear of soy has grown, nevertheless. It has caused a lot of studies claiming males should not be eating it, it can cause breast cancer, or thyroid issues. Ultimately, however, the majority of these studies are inconclusive. There are too many factors to make a completely-accepted claim. Time, ethnicity, gender, hormone levels of the participants, and whole soy, vs. soy protein are only a few variables.
Final Thoughts
Food-grade soy protein has been around for the past 60 years but has seen the highest spike in popularity in the past ten years or so. With the increased interest in plant-based diets, people are adding more soy into their daily lives. Its versatility, protein bioavailability, and well-balanced micro-nutrient profile make it an ideal base for many plant-based products, especially meat analogs. In the end, soy/soy protein can be included to help fortify a healthy diet. This research has shown that soy is overall very beneficial to the human body. If you are still skeptical, it can be said it can be consumed a few times a week without any repercussions.
Resources
- https://books.google.com/books?id=4dbhjEkO_1QC&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=true
- https://www.soyinfocenter.com/pdf/119/CrUsCo12.pdf
- https://ussec.org/wp-content/uploads/2015/10/Soy-Protein-Concentrate-Aquaculture.pdf
- https://www.ncbi.nlm.nih.gov/pubmed/569429
- https://onlinelibrary.wiley.com/doi/full/10.1111/j.1541-4337.2007.00025.x
- https://my.clevelandclinic.org/health/articles/17491-soy-foods
- https://www.hsph.harvard.edu/nutritionsource/soy/
