Research Progress on Extraction, Separation, Purification and Detection Technology of Limonins in Citrus

Citrus is the largest fruit in the world, and a large number of citrus processing by-products are produced every year. These by-products are rich in limonoids, which have many physiological functions such as anti-tumor, anti-inflammatory and anti-virus, and have been used in food, medicine and agriculture. It is of great theoretical and practical value to develop efficient extraction, separation and purification technology of limonoids, and to develop rapid analysis and detection methods of limonoids. In this article, the structural characteristics and content of limonoids in citrus are introduced, and the extraction, separation, purification and detection techniques of limonoids are emphatically summarized. It is found that emerging technologies such as ultrasonic-assisted and supercritical fluid extraction has better extraction efficiency, and the combination of macroporous resin adsorption, high-speed countercurrent chromatography and preparative high-performance liquid chromatography has better separation effect. In terms of detection technology, liquid chromatography is the most widely used analytical method for limonoids in citrus, which can accurately detect the types and contents of limonoids in citrus. However, efficient, green and rapid pretreatment technology and convenient and high-throughput detection technology need to be developed. This paper would provide a reference for the in-depth research and comprehensive development and utilization of limonoids in citrus, and provide a basis for promoting the utilization of citrus by-product resources.