Three‐phase partitioning for the efficient preparation and isolation of active polysaccharides: A review

Abstract Polysaccharides have become a key focus in functional foods and special medical foods. Traditional extraction and separation methods for polysaccharides involve the application of specific techniques to remove different impurities leading to processes that are cumbersome, time‐consuming, and costly. Three‐phase partitioning (TPP), as an efficient separation technology, allows for the simultaneous extraction and separation of multiple components, such as lipids, proteins, enzymes, polysaccharides, and fat‐soluble pigments. This review aims to summarize the separation principles of the TPP and its applications in the extraction and separation of bioactive polysaccharides. It particularly emphasizes the synergistic effects of upstream pretreatment technologies, such as ultrasound/microwave‐assisted and enzyme‐assisted extraction, when combined with TPP as well as optimization strategies for downstream techniques, including ammonium sulfate gradient precipitation and ethanol fractional precipitation in combination with the TPP system. Furthermore, the potential of emerging separation technologies, such as TPP systems utilizing combinations of deep eutectic solvents or dimethyl carbonate with ammonium sulfate, is explored and discussed. This review highlights both a promising opportunity and a significant challenge for researchers in understanding the partitioning mechanisms of TPP and its application in the extraction and separation of bioactive polysaccharides, which have been extensively utilized in the field of functional foods.