Comparative study on structure, properties, functions, and in vitro digestion characteristics of dietary fiber from Chinese chestnut prepared by different methods

Abstract This study compared the effects of enzyme extraction (E‐DF), enzyme‐acid extraction (EAc‐DF), enzyme‐alkaline extraction (EAl‐DF), ultrasonic‐enzyme extraction (EU‐DF), and microwave‐enzyme extraction (EM‐DF) on the yield, chemical composition, structural characteristics, physicochemical properties, physiological activities, and hypoglycemic activities of dietary fiber (DF) from Chinese chestnut. EAl‐DF had the highest yield (25.44 ± 0.70%) among all five extraction methods. The structural analysis indicated that other extracts, particularly EAl‐DF, had a more complex and porous structure than E‐DF. Analysis of monosaccharide composition showed that the main sugars in Chinese chestnut DF included Ara, Gal, Glc, and Man. Notably, EAl‐DF exhibited the highest water and oil retention ability and hypoglycemic activity. The DFs extracted by five methods can resist digestion in the digestive tract. These results indicate that enzymatic‐alkaline method is a high‐quality method for extracting DF from Chinese chestnut. And this study provides a theoretical basis for the efficient preparation and development of Chinese chestnut DF.