Effects of different polysaccharides and proteins on dough rheological properties, texture, structure and in vitro starch digestibility of wet sweet potato vermicelli

The effects of polysaccharides (chitosan, xanthan and sodium alginate) and proteins (gluten, egg white protein) on dough rheological properties, texture, structure and in vitro starch digestibility of wet sweet potato vermicelli (SPV) were investigated. All starch doughs exhibited a linear viscoelastic region (LVR) of <0.05% strain. Chitosan, sodium alginate and xanthan incorporated dough exhibited lower maximum creep compliance and degree of dependence of G′ on frequency sweep than those with egg white protein and gluten, suggesting the formation of stable network structure with stronger deformation resistance. Wet SPV with chitosan exhibited the highest tensile strength, tensile distance and cooking break time, followed by sodium alginate, xanthan, egg white protein and gluten. A mass fracture structure and evenly distributed air cells with similar pore sizes were formed in all wet SPV. Physical linkages between starch and polysaccharides or proteins in all wet SPV were confirmed by similar FTIR spectra. Xanthan and sodium alginate addition decreased the rapidly digestible starch, and increased the resistant starch in wet SPV. In conclusion, all polysaccharides and proteins can improve the quality of wet SPV, and xanthan, sodium alginate and egg white protein show greater application potential.