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The Characteristics of Slow-to-digest Yeast Protein and Its Application

Mar.31, 2021

by Chris Chen

How much do you know about protein?

The protein is an unavoidable topic whether for muscle building or for fat loss. Protein is an important component of all cells and tissues of the human body, which not only plays an important role in the growth and development of the human body, the repair of damaged cells and the formation of antibodies, but also can be decomposed to provide energy and maintain various life activities. Meanwhile, it can affect the exercise capacity of the human body. The body's requirement for protein is directly proportional to the amount of body exercise. Different sports events require different amounts of protein.

It is especially important to supplement enough protein for both sports people and middle-aged and elderly people, but it is more necessary to know when to supplement protein and what kind of protein to supplement.


Fast or slow to digest

Fast-to-digest protein

Fast-to-digest protein can be digested, absorbed into the blood, and metabolized by body tissues in just 20 minutes, and can be used for protein synthesis or oxidation within an hour. It is such suddenly increased amino acids that stimulate the synthesis of muscle protein. Therefore, fast-to-digest protein is considered as synthetic/myogenic protein that can increase the level of amino acids in the blood rapidly, which is necessary to initiate muscle protein synthesis.

Slow-to-digest protein

Slow-to-digest protein is digested gradually. When it is ingested, the content of amino acids in the blood and protein synthesis will peak within 3 to 4 hours, which is a good thing. Slow-to-digest protein is generally considered as a kind of anti-metabolic or muscle protective protein as it provides a stable flow of amino acids over time which can slow down the rate of proteolysis significantly and protect existing muscles.

How to use fast- or slow-to-digest protein

Muscles can only be built when the rate of protein synthesis is greater than that of sarcolysis. Fast-to-digest protein can increase protein synthesis while slow-to-digest protein can prevent sarcolysis, both of which can help you build muscles.

The ingestion of mixed protein with several digestion rates after exercise can shorten the time for muscle protein synthesis during the entire recovery period after exercise, which is conducive to muscle recovery. Especially in endurance sports, sufficient protein can prevent central fatigue as the energy supply ratio of protein increases with the consumption of muscle glycogen in the body and protein catabolism is strengthened. During exercise, protein synthesis and catabolism are in dynamic changes, the concentration of insulin and testosterone in the blood decreases and protein catabolism increases. It is especially necessary to supplement slow-to-digest protein properly.

"Hobble and slow walking" are the normal state of many middle-aged and elderly people, which in most cases are one of the manifestations of muscle attenuation syndrome. The elderly people have difficulty in walking, fatigue and weakness, even difficulty in sitting up, balance disorders and easy falls and fractures due to the gradual decrease of skeletal muscle mass and year-by-year decline of muscle force, which will seriously affect their life quality and greatly increase their risks of loss of the ability to take care of themselves and disability. Studies have shown that the decline in muscle function may begin at about age 35 and decrease at a rate of 1% to 2% per year. The rate of decline begins to accelerate after age 50, further accelerates after age 60 and peaks after age 75. Therefore, middle-aged and elderly people shall supplement more slow-to-digest protein to combat sarcolysis.


Yeast protein AnPro, the high-quality slow-to-digest protein

Studies have shown that yeast protein AnPro is high-quality complete protein with a digestibility similar to that of whey protein but relatively slow digestion; the total digestibilities of yeast protein and soy protein are equivalent, slightly lower than that of whey protein, but there is no significant difference in the absorption rate of the three. AnPro also contains a large amount of branched chain amino acids (BACC)-leucine, isoleucine and valine, which play an important role in muscle protein synthesis. The research results show that the BCAA content of AnPro is 23.3%, much higher compared to SPI and WPC. AnPro is the best protein for sports nutrition, which supports muscle recovery and reduces muscle fatigue. In addition, AnPro is a kind of microorganism-derived protein, which is a good supplement to animal and plant-derived protein. The experimental results of the in vitro simulator show that the digestibility of AnPro in the stomach and small intestine is significantly lower than that of WPC and SPI, while the digestibilities of the three protein sources at the end of the small intestine are similar. This means that AnPro is slow-to-digest protein that may help in anti-metabolism or muscle protection. In addition, slow-to-digest protein can provide a stable flow of amino acids and prevent muscle tissue from collapsing. Compared with WPC and SPI, AnPro can improve satiety and provide amino acids continuously and stably, which is a good protein source for dieters and sports nutrition.


Not-digested protein content during the study using SHIME in vitro simulator


[1] Ren Guangxu, Yi Suqin, Lu Lingang et al. Research progress of dual-protein sports nutrition function of "milk and soybean" [J]. Journal of Chinese Institute of Food Science and Technology, 2015, 15(006):154-161.

[2] Chen Zhixian, Zhang Haibo, Zhang Shuangqing et al. Study on the amino acid composition and in vitro dynamic digestion of three different sources of protein [J]. Journal of Henan University of Technology (Natural Science Edition), 2019, 40(002): 62-68.

[3] Ye Shu. Application of protein supplement in human exercise [J]. Sichuan Sports Science, 2020, 39(4): 36-38.


Published by Chris Chen
R&D expert of Human Health Department of Angel Nutritech

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