Rheological and emulsification properties of native starches extracted from quinoa (Chenopodium quinoa) and kiwicha (Amaranthus caudatus) seeds

This study evaluated the physicochemical, rheological, and emulsifying properties of starches from three varieties of quinoa (white, red, and black) (Chenopodium quinoa) and kiwicha (Amaranthus caudatus) to determine their potential industrial applications. The starches were extracted using an alkaline solution. The rheological and viscoelastic properties were evaluated using 4% (w/v) starch suspensions. White quinoa starch exhibited the highest yield (34.80% w/w) and amylose content (23.90% w/w), while kiwicha starch had the lowest amylose content (15.05% w/w). The quinoa and kiwicha starch pastes exhibited thixotropic behavior, which best fit the Hahn model (R² > 0.73 and MSE < 0.0003). The starch pastes in a steady state exhibited pseudoplastic behavior (n < 1), and the kiwicha starch paste required the highest initial stress (4.21 Pa) to flow. The starch pastes exhibited elastic behavior (G' > G''). Kiwicha and black quinoa starches showed greater emulsifying capacity (99% at 300 mg of starch/mL). In conclusion, the quinoa and kiwicha starch pastes exhibited thixotropic behavior that stabilizes quickly, more elastic behavior, a low initial stress to begin flowing, and high emulsifying capacity, suggesting their potential application in industries requiring specific gelling, stabilizing, and emulsifying properties.