Chemical composition and physicochemical properties of dietary fiber from Polygonatum odoratum as affected by different processing methods

The dietary fibers were isolated from Polygonatum odoratum processed by different methods including steam processing (DFPS) and drying in sunshine (DFDS). The physicochemical and functional properties of dietary fibers were comparatively studied. Results showed that the fiber extracts from P. odoratum had a high amount of total dietary fiber (TDF) (97.92%-98.40%) and insoluble dietary fiber (IDF) (88.12%-92.90%), which resulted in the high swelling power, water-holding capacity (WHC) and oil-holding capacity (OHC). DFPS displayed significantly higher OHC (24.17 g/g) and cation-exchange capacity (CEC) (887.35 mequiv/kg) than DFDS (16.48 g/g for OHC and 265.46 mequiv/kg for CEC, respectively). However, DFDS exhibited significantly higher WHC (23.94 g/g) and swelling power (17.54 ml/g) in comparison to DFPS fiber (21.14 g/g for WHC and 9.81 ml/g for swelling power, respectively). The monosaccharide composition of DFDS consisted of arabinose, xylose, sorbose, mannose and galactose with the molecular ratio of 1.00:1.21:9.61:2.41:4.45. The monosaccharide molecular ratio of DFPS was 1.00:1.52:13.86:2.87:5.81. The WHC, SP and OHC of DFPS and DFDS were significantly higher than those of cellulose. P. odoratum might be a good food resource for dietary fiber. Different kinds of processing methods could be selected depending on the purpose of food products.

Highlights► Chemical compositions of dietary fiber from Polygonatum odoratum were first studied. ► Functional properties of dietary fiber from Polygonatum odoratum were first studied. ► Processing procedure affects the chemical compositions and functional properties. ► Polygonatum odoratum is a good food resource for dietary fiber.