Abstract:

The acid-catalyzed hydrolysis method was adopted to extract soluble dietary fiber from Chinese gooseberry skin residue, a by-product from juice or pulp processing. Effects of four crucial parameters (i.e., material/liquid ratio, pH adjustment of water as extraction solvent, temperature and extraction duration) on extraction yield of soluble dietary fiber were investigated by one-factor-at-a-time method. Subsequently, a central composition experimental design leading to a set of 30 experiments with different combinations of the four variables was performed to attain the maximum extraction yield of soluble dietary fiber. Under the optimized conditions as follows: material/liquid ratio (g/ml) 1:37, pH 2.5, and 80 ℃ for an extraction duration of 100 min, the yield of soluble dietary fiber was found to be 47.74%.

Key words: Chinese gooseberry, skin, soluble dietary fiber (SDF), response surface analysis