Odor and taste thresholds of potential carry-over/off-flavor compounds in orange and apple juice

The odor and taste threshold values of six aroma substances known to be constituents of fruit juices and other fruit products, i.e. limonene, alpha-terpineol, carvone, methyl 2-methylbutanoate, ethyl 2-methylbutanoate, and gamma-decalactone, were determined in various matrices, i.e. model sugar/acid solution, apple and orange juice, as well as apple and orange substitute (made by dilution of fruit juice concentrate with water). Whereas for alpha-terpineol thresholds in the 1.2-11 mg/l area were defined, limonene and carvone were determined to be sensorially effective each at 0.5mg/l. Very low thresholds were measured for gamma-decalactone, methyl 2-methylbutanoate and ethyl 2-methylbutanoate that showed sensory activity in the area of 20, 1.5, and 0.5 mu g/l, respectively. in relation to the aroma composition determined by high resolution gas chromatography-mass spectrometry (HRGC-MS), these results provide an objective possibility to evaluate the sensory efficacy and/or an 'off-flavor' potential of these compounds in fruit juices. (c) 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.