Effect of protein incorporation on functional, thermal, textural and overall quality characteristics of instant noodles

Soy protein enriched noodles were prepared with the addition of different levels of soy protein concentrate (SPC) and the impact of SPC addition was evaluated on pasting, thermal, cooking, textural, sensorial and morphological attributes. Incorporation of SPC significantly (P < 0.05) increased water absorption index and water solubility index while significantly (P < 0.05) reduced oil binding capacity and pasting properties. Differential scanning calorimetry’s results revealed that SP enriched formulations fetched higher peak temperature and enthalpy. The SP incorporation resulted in significant (P < 0.05) higher cooking time (4.10 ± 0.10 to 5.27 ± 0.15 min) and cooking loss (10.34 ± 2.09 to 17.57 ± 0.54) but, significantly (P < 0.05) decreased swelling volume and cooked noodle diameter. SP incorporation in noodles significantly (P < 0.05) increased the hardness and adhesiveness but, significantly (P < 0.05) reduced the springiness, cohesiveness, chewiness, resilience and also decreased L*, a* and b* values. The SP incorporation up to 10% showed higher sensory scores but, further higher levels decreased overall acceptability. The optimized instant noodles (with 10% SP) were also evaluated for their in vitro protein digestibility (IVPD) and morphology. The IVPD of optimized noodles increased from 73.86 ± 0.43% to 80.98 ± 0.27%. The microstructure obtained from scanning electron microscopy also confirmed the effect of SPC on noodle structure.