Isolation and characterization of Atriplex hortensis and sweet Chenopodium quinoa starches

Abstract

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 (Chenopodium 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 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.