Quinoa Seed Quality and Sensory Evaluation
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Quinoa is a grain that has garnered increasing interest in recent years from global markets, as well as in academic research. The studies in this dissertation focused on quinoa seed quality and sensory evaluation among diverse quinoa varieties with potential adaptation to growing conditions in Washington State. The objectives in the dissertation were to study quinoa seed quality, as well as the sensory attributes of cooked quinoa as defined by both trained and consumer panelists. Regarding quinoa seed quality, we investigated seed characteristics (diameter, weight, density, hardness, seed coat proportion), seed composition (protein and ash content), flour viscosity and thermal properties, quinoa cooking quality, and texture of cooked quinoa. Additionally, the functional characteristics of quinoa were studied, including the determination of amylose content, starch swelling power and water solubility, texture of starch gel, and starch thermal properties. Results indicated texture of cooked quinoa was significantly influenced by protein content, flour viscosity, quinoa cooking quality, amylose content, and starch enthalpy. In addition, the influences of soil salinity and fertility on quinoa seed quality were evaluated. The variety ‘QQ065’ exhibited increased protein content and maintained similar levels of hardness and density under salinity stress, and is considered to be the best adapted variety among four varieties. Finally, sensory evaluation studies on cooked quinoa were conducted. A lexicon of cooked quinoa was developed including the sensory attributes of aroma, taste/flavor, texture, and color. Results from the trained and consumer panel indicated that consumer liking of quinoa was positively influenced by grassy aroma, and firm and crunchy texture. These results represent valuable information to quinoa breeders in the determination of seed quality of diverse quinoa varieties. In the food industry, the results of seed quality and sensory studies (lexicon and consumer-liking) can be utilized to evaluate quinoa ingredients from multiple locations or years, determine the efficiency of post-harvest processing, and develop appropriate products according to the properties of the specific quinoa variety. Overall, this dissertation contributed to the growing body of research describing the chemical, physical and sensory properties of quinoa.