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Sensory evaluation of the odors produced during bromophenol formation using a multi-level statistical model
H Al-Samarrai1, J Matud, K Wiesenthal
1Department of Environmental Health Sciences, School of Public Health, UCLA, Los Angeles, CA 90095-1772, USA. samarrai@ucla.edu
Summary
High chlorine levels and reaction time are key to controlling bromophenol formation, which causes medicinal odors in drinking water. Lowering pH can help reduce odor intensity.
Area of Science:
- Environmental Chemistry
- Water Quality Analysis
- Sensory Science
Background:
- Medicinal taste and odor issues reported in suburban Paris drinking water.
- Bromophenols are suspected contributors to these undesirable sensory attributes.
Purpose of the Study:
- Investigate the influence of water quality parameters on bromophenol formation.
- Determine the key factors controlling medicinal odor in water.
Main Methods:
- Laboratory-scale study using Flavor Profile Analysis (FPA).
- Evaluated six parameters: pH, phenol, bromide, chlorine, temperature, and dissolved oxygen.
- Employed a 2-level factorial design (64 experiments) and a three-level statistical model.
Main Results:
- High chlorine concentration was a more significant controlling factor than phenol.
- The ratio of hypobromous acid (HOBr) to phenol and reaction time influenced brominated product formation.
- High pH correlated with lower odor intensities.
- High levels of chlorine, phenol, and temperature were associated with increased odor intensities.
Conclusions:
- Chlorine, phenol, temperature, and pH are critical water quality parameters affecting bromophenol odor.
- Understanding these factors allows for the prediction and mitigation of medicinal taste and odor events.
- Further chemical identification and kinetic studies are recommended for worst-case scenarios.