Abstract:

The extraction of soluble dietary fiber (SDF) from outer leaves of Chinese cabbage was optimized for maximum
SDF yield using combination of single factor method and response surface methodology with Box-Behnken experimental
design. The optimum extraction parameters were determined as follows: hydrochloric acid concentration, 0.06 mol/L;
material/liquid ratio, 1:25 (g/mL); extraction temperature, 90 ℃; and extraction time, 90 min. Under these optimal
conditions, the extraction yield of SDF was 13.65%. The chemical composition analysis showed that the purity of the SDF
product was 86.21%, which also contained a small amount of protein and ash. The appearance of the SDF was a light beige
powder. The microstructure observation showed that SDF powder of cabbage residue exhibited a rough, wrinkled surface
with many holes and pores through magnified observation. The water-holding capacity of the SDF from Chinese cabbage
leaves was 14.63 g/g, the expansion capacity 22.17 mL/g, and the emulsifying capacity and emulsion stability were 48.78%
and 71.34%, respectively. The adsorption abilities for saturated fatty and unsaturated fatty acid were 2.23 and 1.94 g/g,
respectively. These functional properties indicated that the SDF from Chinese cabbage residue is a potential emulsifier and
functional food ingredient.

Key words: Chinese cabbage residue, extrusion, soluble dietary fiber, chemical method, physicochemical property