Could supplemental phytase be beneficial for human diets?
Phytase is an essential enzyme. Phytase is one of the many essential enzymes necessary for the digestive process, and a key enzyme for bone health. Commonly found in plant material, phytase is a natural enzyme often used for breaking down and increasing the nutritional quality of grains, legumes, seeds and corn. Studies confirm that the use of this enzyme can help reduce the need for calcium phosphate and increase digestive health.
Various health professionals are recommending the use of more vegetable and grain based diets for overall health. Phosphorous occurs naturally in vegetable and grain based diets. Much of the naturally occurring phosphorus in grains is unavailable to humans. In monogastric animals most plant phosphorus that is consumed is excreted undigested and inorganic phosphate has to be added to diets to compensate.
Phytases release plant phosphorous. Phosphorus is an essential nutrient in diets. It affects growth, reproduction and food and feed use. Phosphorous is bound by phytic acid. Phytases are digestive enzymes which release plant phosphorus from phytic acid. Phytic acid is the primary phosphate storage compound in seeds, typically contributing 50–80% of total phosphate in plant seeds. Phytic acid helps control effective germination, allowing for a phosphorous release boost when digested by seed phytase upon germination. Exogenous phytase mimics this process in the gastrointestinal tract by releasing this bound phosphorus making it available to the animal. The salt form of phytic acid is called phytate, and almost all phytic acid is present as a mixed salt (phytin). Research with monogastric animals have shown that phytate phosphorous is poorly available to animals and can reduce the digestibility of other nutrients and the performance of animals because of the anti-nutritional effect of phytic acid. Phytates are referred to as “anti-nutritional factor”. Phytase helps reduce the negative effects of phytic acid in the body. Many of the plants that we consume such as corn, grains, seeds, legumes, soybeans and most cereals contain high amounts of this phytic acid. Referred to as an “anti-nutritional factor,” these phytates (phytic acid) reduce our ability to absorb nutrients. Phytic acid has been shown to create insoluble complexes with minerals through its negatively charged phytic acid. This acid has the ability to bind to positively charged molecules in these minerals, as well as in proteins.
Monogastric animals lack sufficient phytases to release the phosphorus in vegetable diets. Adding extra phytases to the diet increases phytate breakdown and consequent utilization of plant phosphorus.
Phytases are unstable enzymes. Being similar, both natural and added phytase share another common feature: they are both extremely sensitive to exposure to high temperatures, such as those encountered during pelleting, for example. This has to do with their very own nature, in that being proteins, they are heat sensitive (only a few proteins are naturally heat resistant). Therefore, exposure to excessive heat reduces their efficacy and as such they release less phosphorus. Because of this, a high recovery (or resistance) to heat is a desired feature in commercially phytase. To make exogenous phytase heat-stable, its formulation (enzyme and carrier) and coating processes require a certain degree of sophistication and technology.
Technology to improve enzyme stability and overcome mineral complexes. Microencapsulation can be used to provide stability to enzyme. Studies have shown a 94% recovery rate of microencapsulated phytase when subjected to steam pelleting. Additionally, the technology can be used to coat anti nutritional factors such as phytates and others which tend to form mineral complexes and thereby prevent the formation of complexes which in turn will allow phytase enzymes to be more effective and increase the availability of phosphorous.