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Isolation and Characterization of Atriplex hortensis and Sweet Chenopodium quinoa Starches

¹Department of Food Science & Nutrition, Brigham Young University, S221 ESC, Provo, UT 84602. ²Department of Food Science & Toxicology, University of Idaho, Food Research Center, Moscow, ID 83844. ³Department of Botany and Range Science, Brigham Young University, PO Box 25245, Provo, UT 84602. ⁴Corresponding author. E-mail: clayton_huber@byu.edu. Fax: (801) 378-8714.

Starches from garden orach (Atriplex hortensis) and sweet quinoa (Chenopodium quinoa Willd. ‘Surumi’) seeds were isolated, examined for compositional characteristics, and compared with bitter quinoa (Cheno-podium quinoa Willd.) starch. Garden orach and sweet quinoa seeds were similar in fat and ash contents, while garden orach seeds contained ≈10% more protein. Starches were isolated from seeds following a 12-hr soak in dilute alkaline solution using a series of grinding, screening, centrifugation, and washing steps. Isolated starches viewed by scanning electron microscopy yielded angular, polygonal granules ≈1–2 μm in diameter. Starches displayed typical A-type crystalline packing arrangements as determined by X-ray powder diffractometry. Apparent amylose contents for garden orach (21.2%), sweet quinoa (20.6%), and bitter quinoa (19.8%) were determined according to colorimetric procedure. Differential scanning calorimetry data indicated a higher and wider gelatinization temperature range for garden orach as compared with sweet and bitter quinoa starches. Starch pasting profiles generated using a Rapid Visco Analyser indicated a reduced peak paste viscosity for garden orach starch relative to sweet and bitter quinoa and common corn starches.