Flavor Profile Analysis Method Research Articles

Comparison of two standard odor intensity evaluation methods for odor problems in air or water

Government agencies responsible for ensuring healthful water and/or air quality are often faced with resolving public complaints of nuisance odors. Understanding variations in odor intensity may ultimately lead to the establishment and application by such agencies of quantitative limits for effective odorant control. An odor panel was trained in suprathreshold odor intensity evaluation using both the ASTM Method E544 (Butanol Method) and the APHA Method 2170 (Flavor Profile Analysis (FPA) Method). A linear mixed model was fitted to the panel data, taking into account the fixed effects of concentration levels and the random effects of panelists and sessions. The FPA method proved easier to administer and revealed less inter-session variance than the ASTM Method, suggesting its greater utility in applications involving odor panels. For both methods, there was a high standard deviation, relative to the mean. This finding indicates that the intensity scales may be useful for understanding relative odor intensities, but should not be used as a precise measure, or as a basis for establishing regulatory limits.

Sensory evaluation of the odors produced during bromophenol formation using a multi-level statistical model

In response to reports of medicinal taste and odor problems in suburban Paris, a lab scale study was conducted to investigate the contribution of different water quality parameters--pH, phenol, bromide, chlorine, temperature and dissolved oxygen levels--on bromophenol medicinal odor formation using the Flavor Profile Analysis (FPA) method. A study of six parameters at 2 levels (64 experiments) analyzed by the FPA method suggests that chlorine at high concentration is more important as a controlling agent than phenol under similar conditions and the ratio of HOBr:Phenol and the time for reaction will control subsequent brominated products of reaction. Results from a three-level statistical model indicate that high pH was associated with lower odor intensities, whereas high levels of chlorine, phenol and temperature were associated with high odor intensities. Potential worst case scenarios of water quality conditions were determined for evaluation by chemical identification and kinetics.

Olfactory and chemical analysis of taste and odor episodes in drinking water supplies

This paper evaluated the presentknowledge of taste and problems in drinkingwater supplies in the form of a ``Taste and OdorWheel'' which organises the relationshipsbetween specific taste and odor problems andtheir causes. The Flavor Profile Analysis (FPA)method enabled the development of the odordescriptors on the wheel. The abilities andshort-comings of the FPA method for odorevaluation by taste and odor panels wereevaluated. The present state of development oftaste and odor standards for drinking water wasthen discussed.

Exposure Assessment of Taste and Odor Standards Used in the Method of Flavor Profile Analysis

Information on the toxicity of individual chemicals that have been used as known or representative odor standards in the method of Flavor Profile Analysis (FPA) was compiled for an exposure assessment. A full risk assessment was not possible since unit risk values for most of these chemicals do not exist. This study provides a recommendation as to what chemicals can be safely used as known and representative taste and odor standards for the next modification of the Flavor Profile Analysis Standard Method 2170. Excluding any potential odor standard listed as possible or probable carcinogens, there would be no known risk to FPA panelists being exposed to the selected odor reference chemicals at the concentrations used in FPA. Also, the concentrations which panelists are exposed to during an FPA (20 minutes per chemical) are lower than the legal threshold limit values for 8 hour occupational exposures. However, many of the odor reference chemicals have yet to be evaluated for their carcinogenic or noncarcinogenic endpoints. Recommendations are made as to which chemicals should be avoided.

The Environmental Fate and Mechanism of Formation of 2-Ethyl-5,5′-Dimethyl-1,3-Dioxane (2EDD) – a Malodorous Contaminant in Drinking Water

A malodorous chemical, 2-ethyl-5,5′-dimethyl-1,3-dioxane (2EDD) created a drinking water taste and odor episode in Pennsylvania (USA) during 1992. The odor episode occurred as the result of a reaction between propionaldehyde and neopentyl glycol in the waste tank of a resin manufacturer. Samples of this waste water were extracted and analyzed. An in situ aqueous preparation of 2EDD was completed to demonstrate that 2EDD could have formed under the conditions found in the waste water. The stability (fate) of 2EDD was studied at different aqueous pHs (pH3, 5, 7, and 9). Some hydrolysis of 2EDD was found at pHs<7 after one week, but 2EDD appeared to be stable at pH 9. The odor characteristics and odor threshold of 2EDD were determined by the method of flavor profile analysis. The odor threshold concentration of 2EDD was found to be between 5 and 10 ng/l and was described as having a sweet, tutti fruitti odor (near the odor threshold concentration) and a burnt, sickening sweet odor at higher concentrations. This study also discovered that slight antagonism in chloraminated drinking water may occur at or near the threshold odor level of 2EDD.

The Formation, Stability, and Odor Characterization of 2-ethyl-4-methyl-1,3-dioxolane (2-EMD)

A class of compounds which are byproducts of the resin manufacturing process, has been responsible for three different taste and odor episodes in drinking water around the world. One such episode which occurred on the Ohio River, Pennsylvania, USA in 1989 was linked to the chemical, 2-ethyl-4-methyl-1,3-dioxolane (2-EMD). In this study, the mechanism and kinetics of formation of 2-EMD were examined specifically under the conditions which were present in the waste water of a resin manufacturer during the Ohio River event. The stability (fate) of 2-EMD was studied at aqueous pHs of 3, 5, 7, and 9. Hydrolysis occurred on the order of hours at pH 3 and its stability was questionable even at pH 7, but appeared to be stable at pH 9. 2-EMD was synthesized and purified in order to determine odor characteristics and odor thresholds using the method of flavor profile analysis (FPA). The distinctive sweet odor described as “sickening sweet” or “medicinal sweet” was found to have an odor threshold concentration of between 5 and 10 ng/l. The levels of 2-EMD found in drinking water samples from the taste and odor event of the Ohio River were above this odor threshold.

Exposure assessment of taste and odor standards used in the method of flavor profile analysis

Information on the toxicity of individual chemicals that have been used as known or representative odor standards in the method of Flavor Profile Analysis (FPA) was compiled for an exposure assessment. A full risk assessment was not possible since unit risk values for most of these chemicals do not exist. This study provides a recommendation as to what chemicals can be safely used as known and representative taste and odor standards for the next modification of the Flavor Profile Analysis Standard Method 2170. Excluding any potential odor standard listed as possible or probable carcinogens, there would be no known risk to FPA panelists being exposed to the selected odor reference chemicals at the concentrations used in FPA. Also, the concentrations which panelists are exposed to during an FPA (20 minutes per chemical) are lower than the legal threshold limit values for 8 hour occupational exposures. However, many of the odor reference chemicals have yet to be evaluated for their carcinogenic or noncarcinogenic endpoints. Recommendations are made as to which chemicals should be avoided.

The formation, stability, and odor characterization of 2-ethyl-4-methyl-1,3-dioxolane (2-EMD)

A class of compounds which are byproducts of the resin manufacturing process, has been responsible for three different taste and odor episodes in drinking water around the world. One such episode which occurred on the Ohio River, Pennsylvania, USA in 1989 was linked to the chemical, 2-ethyl-4-methyl-1,3-dioxolane (2-EMD). In this study, the mechanism and kinetics of formation of 2-EMD were examined specifically under the conditions which were present in the waste water of a resin manufacturer during the Ohio River event. The stability (fate) of 2-EMD was studied at aqueous pHs of 3, 5, 7, and 9. Hydrolysis occurred on the order of hours at pH 3 and its stability was questionable even at pH 7, but appeared to be stable at pH 9. 2-EMD was synthesized and purified in order to determine odor characteristics and odor thresholds using the method of flavor profile analysis (FPA). The distinctive sweet odor described as “sickening sweet” or “medicinal sweet” was found to have an odor threshold concentration of between 5 and 10 ng/l. The levels of 2-EMD found in drinking water samples from the taste and odor event of the Ohio River were above this odor threshold.

Assessing the Quality of Flavor Profile Analysis Data

Flavor profile analysis (FPA) data for influent and effluent water samples from two Philadelphia treatment systems were studied, along with quality control protocols, in order to optimize the FPA method. The quality of the data was evaluated for (1) the qualitative description and (2) the quantitative response for each organoleptic descriptor.

Training Panelists for the Flavor Profile Analysis Method

The drinking water industry needs a standard method for determining the aesthetic quality of water. Currently, only sensory analysis provides the necessary information on the flavor and aroma of drinking water. The flavor profile analysis (FPA) method, as conducted at several water utilities, has provided reproducible results on both the intensity and the description of flavor and aroma. After a short training period, a panel can help provide organoleptic information for the water utility manager. The selection and initial training of panelists is an important aspect that must be considered if a panel is to provide reliable information. This article presents a general introduction about panel training in the FPA method.

Interdependency and Underlying Dimensions of Sensory Flavor Characteristics of Selected Foods

Flavor profile data for beefsteaks, fish gels, frankfurters, peanuts, peanut butters, and baked sweet potatoes were subjected to principal component analysis to study the interdependency and the underlying dimensions of the sensory flavor characteristics in order to simplify the method of flavor profile analysis. The character notes used by the panel to describe the flavor profile of each food were not completely independent. The underlying dimensional structure had a number of dimensions equal to approximately 1/3 the number of character notes which explained about 3/4 of the total variance. Flavor profile analysis for each of the evaluated foods could thereby be simplified through reducing the number of character notes to about 1/3 the original number.