Comparative Analysis of Insoluble Dietary Fiber from Buckwheat Hull Extracted by Sodium Carbonate and Hydrochloric Acid

The buckwheat husk was as raw material, and sodium carbonate soaking method and hydrochloric acid extraction method were used to extract insoluble dietary fiber (IDF) from buckwheat hull.The results showed that the best process for extracting buckwheat hull IDF with sodium carbonate was:The alkali hydrolysis temperature was 60℃, Na₂CO₃ mass fraction was 10%, alkali hydrolysis time was 40 min, solid-liquid ratio was 1:13 g/mL.Under these conditions, the yield of buckwheat hull IDF was 82.75%, swelling force was 6.87 mL/g, water holding capacity was 379.18%. The optimal conditions for the extraction of buckwheat hull IDF with hydrochloric acid extraction were pH2, acid leaching temperature 60℃, acid extraction time 100 min, and solid-liquid ratio 1:15 g/mL. The yield of buckwheat hull IDF was 86.00%, the swelling force was 5.92 mL/g, and the water holding capacity was 365.31%. Under the best process conditions, a direct comparison showed that the yield obtained by the hydrochloric acid method was slightly higher than that of the sodium carbonate method, but the obtained IDF was inferior to the sodium carbonate method in terms of hydration performance such as expansion force and water holding capacity.