Effect of sodium alginate on the quality of highland barley fortified wheat noodles

The impact of sodium alginate (SA) addition on the dough rheological properties and quality of highland barley-wheat composite noodles (HBWN) was systematically investigated. HBWN were prepared by 40% substitution of wheat flour with highland barley flour. And SA was added to HBWN in proportions of 0.1%, 0.2%, 0.3%, 0.4% and 0.5%. The results showed that SA enhanced the noodle quality regardless of the SA concentration, embodying in a lower cooking loss and water absorption, an increased hardness and springiness. Dynamic rheology analysis showed that SA addition elevated G′ and G″ of dough. Pasting profiles of samples indicated that SA boosted the peak viscosity of starch granules. The relative crystallinity and ordered structures of the starch respectively obtained from X-ray diffraction and Fourier transform infrared spectroscopy decreased with the SA addition (0.1%–0.5%). Meanwhile, impact of SA on the molecular distribution of gluten network in HBWN was evaluated by SE-HPLC. SA induced protein depolymerizations in HBWN, resulting in the reduction of glutenin macropolymer (GMP). SEM and CLSM results exhibited that higher SA concentration (0.3%–0.5%) could promote the protein-starch interaction and contribute to a uniform and compact structure, which improved rheological properties of dough and texture properties of HBWN.