Comparison of the characteristics, functional properties, and in vitro hypoglycemic effects of various carrot insoluble fiber-rich fractions

Abstract

Fiber-rich fractions (FRFs) including insoluble dietary fiber (IDF), alcohol-insoluble solid (AIS), and water-insoluble solid (WIS) were isolated from carrot pomace via different methods. This study revealed that carrot pomace was rich in insoluble FRFs (50.1–67.4 g/100 g), which were mainly composed of pectic polysaccharides, hemicellulose, and cellulose. These insoluble FRFs, especially WIS, were found to have significantly ( P<0.05) higher functional properties, glucose-adsorption capacity, and amylase-inhibition activity than those of cellulose. The ability of these FRFs to adsorb glucose and reduce amylase activity implied that they might help control post-prandial serum glucose level. Moreover, it was shown that the yield, composition, functional properties, and in vitro hypoglycemic effects among the three FRFs would be affected by their preparation methods. Our results recommended the consumption of these insoluble FRFs, especially WIS, as sources of food fibers or low calorie bulk ingredients in food applications requiring oil and moisture retention.