Submitted to: Flavour and Fragrance Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2004
Publication Date: 10/27/2004
Citation: Plotto, A., Margaria, C.A., Goodner, K.L., Goodrich, R., Baldwin, E.A. 2004. Odour and flavour thresholds for key aroma components in an orange juice matrix: terpenes and aldehydes. Flavour and Fragrance Journal. 19:491-498. Interpretive Summary: Traditional methods to study aromas and flavors in a food involve gas chromatography to isolate, identify and quantify volatile compounds. Comparison of the amount of volatile compounds isolated from the food with respective odor thresholds determines which compounds are responsible for the odorous character of the food. The drawback of this method is that most published threshold values use water as the dilutant of the compound. However, volatile compounds interact with non-volatile compounds in a food matrix, such as carbohydrates, lipids and proteins, and odor threshold values in water can only be used for other foods as indicators. This study presents the method and results of threshold values of compounds important for orange juice flavor, terpenes and aldehydes, obtained by using a deodorized orange juice matrix as the dilutant. The results show that by using the orange juice matrix, odor and taste thresholds are increased by 15 to 200 fold, and by two to 60 fold, respectively. The odor activity values, which are traditionally used in flavor research to determine the aroma impact components in a food, are consequently lowered. These results will serve as indicators for orange juice manufacturers who may need to standardize flavors with individual compounds.
Technical Abstract: Thresholds for flavor volatiles have been traditionally calculated in water or air, but they may vary widely in more complex matrices. This lab determined the thresholds of key aroma compounds of orange juice (OJ) in a deodorized OJ matrix. The Three-Alternative-Forced-Choice (3-AFC) method was used (ASTM: E-679). Twelve to twenty experienced panelists were presented with orange juice samples arranged in five rows of three samples corresponding to five spiking levels, each separated by a factor of 3, with a 3-AFC presentation at each level. The test was repeated at least three times. Odor thresholds in the orange juice matrix were 10 times (linalool, hexanal) to 300 times (a-pinene, octanal) higher than published values in water. Taste thresholds were more consistent with published values, being only higher by ten to forty folds. These results will provide the industry with threshold guidelines more adequate for the use of flavors in citrus juices.