Comparative study of chemical treatments in combination with extrusion for the partial conversion of wheat and sorghum insoluble fiber into soluble

Dietary fiber has gained greater attention owing to their positive and potential health perspectives. Cereals are the most important and enriched source of dietary fiber with more insoluble dietary fiber than soluble. For dietary fiber modification, chemical treatment with various techniques is considered as significant approach owing to its safety point of view and involves less damage to the molecular structure of the dietary fiber through chemical reagents and content of soluble dietary fiber is increased more efficiently. The current study was aimed to nutritionally characterize the cereal grains and to partially convert insoluble dietary fiber into soluble dietary fiber through chemical treatments in combination with extrusion. For the purpose, two varieties of each cereal were characterized for their chemical composition, mineral profile, and dietary fiber content according to the respective methods. Then, dietary fiber ratio in cereals was modified through chemical treatments, that is, acid, alkaline, and consecutive acid-alkaline followed by extrusion. Results regarding dietary fiber content of cereal grains exhibited that wheat (12.03-12.20 g/100 g) contained higher total dietary fiber followed by sorghum (6.70-6.90 g/100 g). Additionally, modification of SDF (1.97%) and IDF (11.48%) ratio in wheat and SDF (1.19%) and IDF (24.25%) ratio in sorghum through extrusion processing was nonsignificant while acid-alkaline treatment showed highly significant results, that is, 768.2% increase in SDF and 56.5% decrease in IDF in wheat and 952.38% increase in SDF and 71.17% decrease in IDF in sorghum. Among chemical treatments, higher result was given by acid-alkaline method and the lower outputs were observed in case of extrusion in both cereals. Conclusively, soluble dietary fiber was significantly increased through chemical treatments alone or in combination with twin-screw extrusion.