Date of Graduation


Document Type


Degree Name

Master of Science in Food Science (MS)

Degree Level



Food Science


Han-Seok Seo

Committee Member

Luke Howard

Second Committee Member

Thomas Hummel


Consumer Rejection Threshold, Flavored Water, Sensory Acceptance


Functional flavored water has emerged as a major space in the beverage industry in recent years. However, no research has explored the point that consumers begin to reject a specific flavor concentration within a flavored water matrix (i.e., a consumer rejection threshold). The first part of this thesis aimed to determine the consumer rejection thresholds of mixed-berry flavors in both sweetened and unsweetened water samples and examine the effects of demographics, food neophobia status, and personality traits on the consumer rejection thresholds. The second part of this thesis aimed to distinguish and compare consumer rejection threshold methodologies with and without a control as well as determine the drivers of liking in sweetened mixed-berry flavored water samples and how those may impact overall acceptance. A total of 103 consumer panelists completed two sessions (unsweetened versus sweetened) of a two-alternative forced choice paired preference test on seven concentrations of total volatiles (0.006, 0.013, 0.026, 0.052, 0.104, 0.208, and 0.416 μg/mL) and one control concentration of total volatiles (0.003 μg/mL) in mixed-berry flavored water. The consumer rejection threshold (CRT) was found to vary between unsweetened (CRT=0.110 μg/mL) and sweetened (CRT=0.028 μg/mL) berry flavored water. The CRTs also varied with age groups, gender, food neophobia status, and personality traits in both types of flavored water. The 88 of the 103 panelists returned to complete another session (the second part of this thesis) to determine a CRT under a sweetened flavored water matrix. In this session, panelists were asked to rate their preference to consume in the absence of the control option. They were also asked to rate each of the seven concentrations for overall liking and Just-About-Right attributes (flavor, sweetness, bitterness, and sourness). When taking away a control, a CRT was not met, although the CRT was met (CRT= 0.033 μg/mL) in the presence of the control option. While overall liking decreased with flavor concentrations, only the strongest two concentrations (0.20 and 0.40) were disliked among panelists. In terms of JAR attributes, perceived flavor, sourness, and bitterness intensities were all significantly different among concentrations, while sweetness was not significantly different. In conclusion, the first study showed that CRTs of mixed-berry flavor essence can vary in compositions of base matrix in flavored water samples. The CRTs can also differ with demographic profiles, food neophobia status, and personality traits, meaning product developers may need to consider type of matrix and certain demographics when formulating and marketing a flavored water product. The second study demonstrated that CRTs of mixed-berry flavor essence might vary with the consumer rejection threshold methodologies. A further study, therefore, should be conducted to optimize the test conditions for consumer rejection thresholds.