Research Progress On Extraction And Purification Methods Of Phytosterols

Abstract: Phytosterols is a naturally active substance with many functional properties. In order to make better use of phytosterols and improve the extraction efficiency and quality of phytosterols, the structure and source of phytosterols were discussed based on the research of related literature in recent years at home and abroad. The types, characteristics and applications of extraction and purification methods of phytosterols were analyzed. The traditional methods such as solvent extraction method and new methods such as supercritical fluid method and auxiliary technologies were summarized. Finally, suggestions for future research directions were put forward in order to provide reference for the efficient extraction and purification of phytosterols.

Keywords: Phytosterols；Structure；Source；Extraction；Purification

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1 Introduction

Phytosterols are triterpenoids that naturally exist in plant cell membranes and are precursors for the biosynthesis of various hormones, vitamin D and steroids.

precursors for the biosynthesis of various hormones, vitamin D and steroid compounds, with various physiological effects such as hypolipidemic, hypocholesterolemic, cardiovascular, anticancer and anti-inflammatory [1]. It has various physiological effects such as hypolipidemic, hypocholesterolemic, cardiovascular, anticancer and anti-inflammatory [1]. Acute, subacute and chronic toxicity as well as reproductive toxicity and mutagenicity studies of phytosterols did not show any abnormalities [2]. [2], and the US Food and Drug Administration, the European Commission and our National Health and Wellness Commission have determined that phytosterols are safe [3]. At the same time, phytosterols are a class of bioactive substances that exist naturally in various plant sources, and currently phytosterols have been used in food, cosmetics, medicine, industry and other fields [1], and the large demand for phytosterols makes its high extraction rate and The high extraction rate and high purity of phytosterols have become the focus of current research. Traditional extraction and purification methods such as extraction, molecular distillation, saponification, solvent crystallization method, column chromatography, etc. are feasible, but there are disadvantages such as low extraction efficiency, large losses and environmental pollution. In order to solve these problems problems, pressurized liquid method, high-speed counter-current chromatography, supercritical CO2 method; enzyme-assisted, microwave-assisted, ultrasound-assisted, magnetic field The use of these new methods and auxiliary techniques has greatly improved the extraction efficiency and extraction quality. In this paper, we discuss the structure, source and extraction of phytosterols In this paper, we summarize and analyze the structure, source and extraction and purification methods of phytosterols in order to provide reference for the efficient extraction and purification of phytosterols.

2 Structure and source of phytosterols

Phytosterols are usually white solids, in the form of flakes or powder, with high melting point, insoluble in water and soluble in organic solvents [5]. Currently, plants contain more than 200 phytosterols, and phytosterols include 4-methyl-free sterols, 4-monomethylsterols and 4,4 The three types of phytosterols include 4-monomethylsterols, 4-monomethylsterols and 4,4-dimethylsterols [6], which have a tetracyclic steroid nucleus, 3b hydroxyl group and 5,6-double bond in the structure, and the chemical differences between the common 4-monomethylsterols The chemical differences between them are the number of carbon atoms in the C-17 branched chain and the presence of a double bond at position 22. Phytosterols contain a double bond at C-5 All phytosterols contain a double bond at C-5, with a total of 28 or 29 carbon atoms [7].

Phytosterols are widely found in the roots, stems, leaves, fruits and seeds of plants. The sources and properties of different phytosterols vary somewhat.

The highest content of phytosterols is found in oils, and vegetable oils such as rice bran oil, germ oil, and tar oil are the main sources of phytosterols [7]. The main source of phytosterols is rice bran oil, germ oil and other vegetable oils, as well as tall oil [8], and the deodorized fraction of crude oil obtained by deodorization is rich in phytosterols [1], and phytosterols are also contained in grains, vegetables, fruits and some herbs. The most common types of phytosterols include β-sitosterol, soy sterols, rapesterol and rapeseed sterols [9] (see Table 1); phytosterols also include spinach sterol, oat sterol, rockwort sterol, iso-rockwort sterol, and and some sterols and sterenols [10].

In addition to free sterols, phytosterols also exist as sterol esters and sterol glycosides [19]. Phytosterol esters are found in plants naturally occurring, such as soybean and rice germ. In cereal seeds, wheat, and rye, a large number of glutaric sterols and rapeseed sterols are present sterol esters of alkanols [20]. Industrial preparation of phytosterol esters is generally done by esterification or ester exchange of phytosterols with linoleic, oleic or phenolic acids. esterification or ester exchange. Phytosterol esters have similar functional properties to phytosterols and are a functional food base. Vegetable oil spreads containing phytosterol esters have been marketed as cholesterol-lowering functional foods in more than 20 countries worldwide [21]. Phytosterols Phytosterol glycosides are mainly found in plant hair oil, and some herbs also contain phytosterol glycosides, such as Morinda citrifolia, Chrysanthemum, Plumeria, Centrum, and Buckthorn. The common sterol glycosides include β-sitosterol-β-D-glucoside, and sarcosine-3β-glucoside [22-23]. 4 Sterol glycosides have important biological functions, including the regulation of host defense against pathogens, lipid metabolism, and development [24]. Although phytosterols are abundant sources, they are thermally unstable and susceptible to environmental influences during extraction and purification. If the chosen method is inappropriate or subject to technical limitations, it will lead to phytosterol degradation, low extraction rate and product purity, limiting The development and application of phytosterols Suitable extraction and purification methods should be selected to further improve the extraction and purification efficiency of phytosterols.