| 【Objective】The study was to establish a method for enzymatic extraction of corncob dietary fiber and
to optimize the preparation of soluble dietary fiber (SDF) by mixed enzymatic modification of corncob insoluble dietary fibe
(IDF). 【Method】 With the corncob as raw material, the conditions of alkaline protease, α-amylase and saccharification
enzyme pretreatment for extraction of corncob total dietary fiber (TDF) were optimized by single factor experiment. With the
combination of single factor and orthogonal design experiments, the process of SDF preparation from IDF by mixed cellulase
and xylanase modification was optimized. 【Result】 The conditions of bio-enzymatic extraction of corncob TDF were as
follows: solid-liquid ratio of 1∶10, pH 9.0 and 1.4% alkaline protease with enzymatic hydrolysis at 50℃ for 60 min; pH 6.5,
0.3% α-amylase and glucoamylase (1 ∶ 1)with hydrolysis at 60℃ for 60 min, and IDF yield was 69.35%. The optimum process for the modification of IDF by mixed enzymatic method was as follows: pH 5.0, temperature 50 ℃ , cellulase 1.2%,
xylanase 1.2%, with enzymatic hydrolysis for 6 h and the solid-liquid ratio of 1 ∶ 10. The SDF yield could reach 22.16%.
The water holding capacity, expansibility, and oil binding capacity of the obtained SDF were 6.55 g/g, 6.69 mL/g, and 4.65 g/
g, respectively, which were 40.26%, 48.67% and 74.16% higher than those before modification, respectively. 【Conclusion】
The yield of SDF prepared by mixed enzyme modification from corncob IDF was higher than that of single cellulase or single
xylanase, and the water holding capacity, oil binding capacity, and expansibility of SDF product were significantly improved as
well. |
