A comprehensive review of inulin-type fructans and their neo-series: Plant sources, preparation, structural characterization, and bioactivities

Inulin-type and neoinulin-type fructans are carbohydrates composed of fructose and glucose, which are important active ingredients in many dicotyledonous and monocotyledonous plants. These fructans have a variety of health-promoting effects, including immunoregulatory, hepatoprotective and prebiotic activities. They are now widely used in the food, cosmetic, and pharmaceutical industries. Obtaining high-purity inulin-type and neoinulin-type fructans and determining their structural features will help in understanding their structure-activity relationships. Currently, there are still few studies on the extraction, isolation, purification, structural characterization, and biological activities of inulin-type and neoinulin-type fructans from different plants. Notably, the structural identification of these fructans still faces challenges due to the instability of fructose under thermal and acidic conditions. This paper reviews the potential plant sources of inulin-type and neoinulin-type fructans, along with their applications in the food and pharmaceutical industries. In addition, it summarizes the main methods of extraction, isolation and purification of inulin-type and neoinulin-type fructans from various plants, the analytical methods used to characterize their structures, as well as their biological activities and potential structure-activity relationships. This review aims to provide valuable insights for the further development and utilization of inulin-type fructans.