Molecular Weight Distribution, Measured by HPSEC, and Viscosity of Water-Soluble Dietary Fiber in Carrots following Different Types of Processing

The molecular weight distribution, measured by HPSEC, and the viscosity of the water-soluble dietary fiber isolated from variously processed/cooked carrots were investigated. The carrots were studied raw, frozen, blanched, soured, microwaved, and boiled. The fibers were isolated after enzymatic digestion of protein and starch to simulate the situation in the gastrointestinal tract. The degree of polymerization (DP) and the viscosity were highly dependent on the type of processing/cooking and in general followed the degree of heat treatment. Thus, the DP values were similar with raw and frozen carrots, whereas blanched carrots had a lower DP. Further, only minor differences in DP could be observed among blanched, soured, and microwaved material, and the most pronounced degradation was obtained in boiled material. The viscosity was in accordance with the DP measurements and decreased in the order raw > blanched > boiled.