Huauzontle (Chenopodium nuttalliae Saff.) protein: Composition, structure, physicochemical and functional properties

The physicochemical and functional properties of huauzontle protein isolates (HPI) were investigated. HPI had high contents of most essential amino acids excepting valine, and a protein digestibility of 83.0 ± 0.2%. SDS-PAGE showed that the main protein bands were located between 20 and 50 KDa. FTIR pinpointed that the Amide I secondary structure was composed by repetitive units (e.g., α-helix and β-sheet), whose relative proportion varied with pH. Foaming capacity (FC) and foaming stability (FS) were higher as HPI concentration increased. FC was 206 ± 2.8% and FS was 100% after 1 h of aging using 3% HPI at pH 7.0. Self-supporting homogeneous gels were formed at pH 7.0 and 9.0, but not at other pH values. The storage modulus (G') predominated over the loss modulus (G'') over a heating-cooling temperature ramp (20-90-20 °C), with both moduli tending to increasing upon heating, and with gel hardening occurring during cooling. G' and G'' decreased sharply at moderate and high strain%, with a crossover of both moduli taking place at lower strain% (~60%) at pH 9.0. This behavior might be attributed to the relative percentage of protein secondary structures which changed with pH. This study clearly establishes HPI as a potential and novel functional ingredient for the food industry, which besides possesses a high nutritional quality. [Display omitted] •Huauzontle protein (HPI) has high amino acid contents and protein digestibility.•Functional properties (foaming, gelling, rheology) of HPI were pH dependent.•The relative percentage of secondary structures in HPI also varied with pH.•Foaming capacity and stability were higher for HPI than for quinoa protein.•HPI formed self-supporting gels at pH 7 and 9 with predominant elastic behavior.