Extraction and Evaluation Antioxidant and Hypoglycemic Activities of Polysaccharides From Black and White Quinoa

It is well established that quinoa varieties with distinct seed colors differ in their phytochemical profiles and bioactivities. Given this, the present study conducted a comparative analysis of polysaccharide yields from black and white quinoa, along with a systematic assessment of their antioxidant and hypoglycemic properties. The results revealed a significantly higher extraction yield from white quinoa (2.18%) compared to black quinoa (1.86%). A positive correlation was observed between polysaccharide concentration and these bioactivities. Moreover, white quinoa polysaccharides demonstrated significantly stronger antioxidant and hypoglycemic activities than those from black quinoa. Antioxidant activities were evaluated by determining the scavenging capacities against DPPH•, superoxide anion (O 2 −•), hydroxyl radical (•OH), and ABTS radicals. Maximum radical scavenging activities against all four tested radicals were achieved at 2.5 mg/mL of polysaccharides concentration. Furthermore, at a concentration of 1 mg/mL, white quinoa polysaccharides exhibited significantly stronger enzyme inhibition than black quinoa polysaccharides. Specifically, the inhibition rates of white quinoa polysaccharides against α ‐glucosidase and α ‐amylase were 59.16% and 49.25%, respectively, whereas those of black quinoa polysaccharides were 51.23% and 42.71%, respectively. These findings highlight white quinoa′s enhanced potential for developing natural antioxidant and hypoglycemic functional ingredients, providing valuable insights for the targeted utilization of quinoa resources in nutraceutical applications. This study provides the first systematic comparison of polysaccharide yields and bioactivities between black and white quinoa, establishing a foundation for color‐based screening of high‐value quinoa varieties.