The source, extraction, purification, physiological function, and application of stachyose in the food industry.

Stachyose is a new functional oligosaccharide that exists naturally in plants, including Stachys sieboldii and Rehmannia glutinosa. Because of its low sweetness, low-calorie content, and robust stability, it has been used to improve food quality and develop functional foods. In addition, owing to its targeted regulatory effect on beneficial microorganisms in the gut and its influence on body health, evidence suggests that stachyose's physiological function may be attributed to its interaction with the host. Notably, stachyose's physiological characteristics and functions are largely affected by its extraction process, purity, physical composition, and chemical structure. Therefore, the present review mainly describes the source, extraction, and purification processes, physiological functions, and applications of stachyose in the food processing industry, which would aid in elucidating the biochemical reactions of stachyose in the body, and its future application prospects in the field of food.