DISCRIMINATION TESTING • Triangle test “choose the sample that is most different” • Duo-trio test “choose the sample that matches the reference” • Paired comparison test “which sample is sweeter?” To determine whether two samples are perceptibly different Performed when there are only two samples 

TRIANGLE TEST Two samples are from same formulation and one is from the different formulation To indicate either which sample is the odd sample or which two samples are most similar Example of Triangle score sheet Source: Sensory Evaluation of Food, Lawless & Heymann; 2010 

DUO-TRIO TEST One sample is marked reference and this sample is the same formulation as on of the two coded samples To determine if two samples are perceptibly different but the direction of the difference is not indicated Example of Duo-Trio score sheet Source: Sensory Evaluation of Food, Lawless & Heymann; 2010 

PAIRED COMPARISON TEST Known as the two-alternative force choice (2-AFC) test Efficient and powerful to determine the two samples differ in specified attribute Example of 2-AFC score sheet Source: Sensory Evaluation of Food, Lawless & Heymann; 2010 

STRENGTHS AND WEAKNESSES OF DISCRIMINATION TESTS STRENGTHS Simple and intuitively grasped by the panelists WEAKNESS Not indicate the magnitude of the sensory difference between the sample formulation Not indicate the nature of the sensory difference between the samples