2.11.1. Discriminative test
This test was performed to compare the difference between commercial chocolate milk alone and the same sample with liposomes.As the main goal of this assay is to analyze similarities (if any) between samples, 78 evaluators were used, being the accepted number of evaluators between 50 and 100. The following considerations were taken into account:
H0: Null hypothesis, there is no significant differences between
samples.
Ha: Alternative hypothesis: samples have significant differences
between each other.
H0 was analyzed with 0.10 value of the significance level or a (which is the probability of rejecting H0 when it is true). This value was high because it is the highest risk to say that the products are different when, in fact, they are similar (Meilgaard et al., 1999).
For the triangular test, evaluators should be familiar with the test and evaluate the product. That is why 78 consumers of commercial chocolate milk (men and women over 18 years old) were selected and instructed in the test (Santa Cruz et al., 2005). In each test two samples were the same and the third one was different (product with and without liposomes). The samples were given to each evaluator in disposable cups of 200 mL; each cup had 30 mL of product. The milk was at room temperature and the randomness of the samples was ensured throughout the test. Thus, each evaluator performed the triangular test for the three formulations, testing a total of 9 samples each. Between samples from the same triangle, evaluators were requested to drink water for neutralization and, prior to move from one triangle to the next, they were requested to eat a cracker and drink water to avoid sensory fatigue. Finally, each evaluator filled a card with their evaluation