Optimization of Insoluble Dietary Fiber Extraction from Apricot Kernel Skin and Its Physicochemical Characteristics

The extraction conditions of insoluble dietary fiber(IDF) from apricot kernel skins were optimized using response surface methodology by modeling extraction yield with respect to three variables including alkali concentration, ultrasonication time and extraction temperature. Furthermore, factors affecting the water-holding capacity and swelling capacity of IDF were also studied. The results showed that the optimal extraction conditions were as follows: sodium hydroxide concentration, 0.70 mol/L; ultrasound-assisted extraction time, 51 min; and extraction temperature, 86 ℃. The extraction yield of IDF was 49.73% under these conditions. In addition, this study found that the water-holding capacity and swelling capacity of the IDF were affected less by glucose concentration, but significantly by pH and temperature within the investigated ranges.