Phytosterol ester Properties

Phytosterol esters are generally prepared by esterification or transesterification of phytosterols with fatty acids. Since there are many kinds of sterols and fatty acids that can be used to produce phytosterol esters, a variety of phytosterol esters with different physical and chemical properties can be obtained. The three main phytosterol esters are β-sitosterol esters, stigmasterol esters, and campesterol esters. Sterol esters can be converted into sterols and fatty acids in the human body, so their physiological functions include the physiological functions of phytosterols and fatty acids. They have the same effect of reducing plasma total cholesterol and low-density lipoprotein cholesterol as free phytosterols, and even better in some aspects.
The use of phytosterols in the form of crystals has the following two problems. On the one hand, the solubility and bioavailability of the crystalline form in the human body are relatively poor, thus leading to high doses in the treatment of hyperlipidemia and the resulting hyperphytosterolemia, I .e., a significant increase in the concentration of phytosterols in the serum. On the other hand, the solubility of phytosterols in oil is very small, which makes it difficult to use them in foods.
Phytosterols have significant hypolipidemic function, which has been confirmed by a large number of studies. However, phytosterols are insoluble in water and have a rather limited solubility in the oil phase, which limits their use. For many years, attempts have been made to modify phytosterols in order to expand their range of applications. Since the early 1990 s, foreign countries have begun to explore the application of phytosterols, and have developed a variety of phytosterol products through purification and modification. Esterification of phytosterols into sterol esters is one of the important modification methods. The esterification product of sterol ester as a hypolipidemic factor can be widely used in margarine, spread oil and ice cream and other products, while reducing the use of emulsifiers. Phytosterol esters can be added to most foods to improve the nutritional value without affecting the original texture of the food, which greatly expands the scope of application of phytosterol esters.
In order to facilitate the application in food processing, it is required to change the form of phytosterol without affecting the physiological function of phytosterol. The phytosterol fatty acid ester meets this requirement, which greatly improves the fat solubility of phytosterols, so that it can be added to oil-containing foods. Phytosterol esters are absorbed by the hydrolysis of pancreatic cholesterol lipase into free sterols, which is the only difference in metabolism between free sterols and ester sterols. Therefore, phytosterol esters also have the physiological functions of phytosterols.