Visual haze detection threshold assessment by ascending method of limits and a transformed staircase procedure in apple juice simulations under "store like" conditions

Visual haze detection thresholds were assessed in thirty panelists by two m ethods: the ascending method of limits and a transformed staircase procedur e (UDTR, from Wetherill and Levitt 1965). ne 3AFC test was used as the resp onse procedure for both methods. Experimental samples consisted of an apple juice simulation (water with food coloring). Haze was added to the samples using formazin, and was calibrated to eleven levels ranging from. 0.75-13. 30 NTU. Haze detection thresholds under store-like conditions (3.55 +/- 0.5 7 [mean +/- S.E.] and 3.16 +/- 0.50 NTU by the two methods, respectively) w ere higher than those found previously under more controlled viewing condit ions. No differences were found between methods, genders, or order of metho d presentation (p > 0.05); a practice effect showed a slight improvement in detection thresholds between sessions (p = 0.05). Nonparametric tests conf irmed the similarities in the threshold estimates from the two methods. The two methods estimated visual haze detection thresholds equally well. Howev er, the ascending method of limits may be preferred method due to the short er time involved in administration.