Optimization of a sensory evaluation protocol for measuring the umami taste

Umami substances linger in mouth for a long time, making it difficult to achieve an accurate sensory measurement. The objective was to establish a reproducible protocol to accurately measure the intensity of umami taste. Two-alternative-forced choice (2-AFC), ranking, and rating methods were compared for discrimination ability of umami taste intensities of monosodium glutamate solutions. Monadic rating and rank-rating methods were compared for accuracy in measurement of umami intensities since neither 2-AFC nor ranking method generates numerical intensity values. Mouth rinsing protocol efficiencies were investigated for 7 palate cleansing methods during umami intensity evaluation. 2-AFC was the most powerful method, followed by ranking and rating methods, for discrimination of different umami samples. Monadic rating and rank-rating methods both showed similar error rates but monadic rating was slightly more accurate than rank-rating. Crackers, a toothbrush, and water at 45A(0)C were more effective palate cleansers than carrots and water at 18A(0)C.