Quinoa quality evaluation in the Pacific Northwest
G. WU (1), C. F. Morris (2), K. M. Murphy (1). (1) Washington State University, Pullman, WA, U.S.A.; (2) USDA-ARS, Pullman, WA, U.S.A.
Quinoa, <i>Chenopodium quinoa </i>Willd, is a pseudocereal from South America. Washington State University (WSU) has studied the adaptation and quality of quinoa in the Pacific Northwest (PNW) since 2010. Individual varieties have shown high seed yield and early maturity, resistance to downy mildew and pre-harvest sprouting, and moderate heat tolerance in green house test. Breeding work is on-going. Seed quality tests and end-use evaluations were conducted on eleven different cultivars. Cultivar means were 1.9 – 2.2 mm in diameter, with 1 – 9% of seed coat. As the major components, protein and starch constituted 11.3 – 17% and 53.2 – 75.1% of dry weight, respectively. Apparent amylose content of quinoa starch was lower than those of other grains, ranging from 2.7% to 16.9%. Quinoa starch exhibited gelatinization temperatures of 52 – 79 ºC, and enthalpy of 10 – 12 J/g. RVA of starch showed peak viscosity from 193 to 344 RVU, and setback from 53 to 140 RVU. Cooking quality of quinoa varied among cultivars. Optimal cooking time ranged from 12 to 19 min. During cooking, quinoa can take up 2.5 – 4 times seed weight of water. Texture profile analysis (TPA) was studied on the same samples. The results showed that cooked quinoa varieties varied in hardness, adhesiveness, cohesiveness, gumminess, and chewiness. Correlations were studied between TPA parameters and seed characteristics, composition, starch thermal properties and viscosity, and cooking qualities. Seed density, seed coat proportion, protein content, apparent amylose, starch enthalpy and final viscosity, optimal cooking time, and water uptake ratio, were most highly correlated with texture. Studies currently in progress on consumer preference of quinoa varieties, and the relationship with seed quality and instrumental analysis of texture and taste will also be presented.
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