In vitro hypoglycemic effects of different insoluble fiber-rich fractions prepared from the peel of Citrus sinensis L. cv. Liucheng.

Insoluble fiber-rich fractions (FRFs), including insoluble dietary fiber, alcohol-insoluble solid, and water-insoluble solid, were isolated from the peel of Citrus sinensis L. cv. Liucheng. We found that these three FRFs could effectively adsorb glucose, retard glucose diffusion, and inhibit the activity of alpha-amylase to different extents. These mechanisms might create a concerted benefit in decreasing the rate of glucose absorption and eventually lower the concentration of postprandial serum glucose. The potential hypoglycemic effects of these FRFs suggested that they could be incorporated as low-calorie bulk ingredients in high-fiber foods to reduce calorie level and control blood glucose level.