Picking Aroma Character Compounds in Citrus limon Oils by Using Odor Thresholds in Aroma Mixtures

Seven aroma chemicals identified in Citrus limon oils were selected as potent character-impact compounds on the basis of their limited odor unit values (Lod). Those seven compounds selected have high aroma intensities. The recognition threshold of a target lemon oil against a reference lime oil was 32.9 ppm. A model oil (Oil mode1 7) prepared by mixing the natural abundance of the 7 impact chemicals from Citrus limon, gave a recognition threshold against the target lemon oil at 55.1 ppm, indicating a high similarity of the model to the target oil in aroma quality. Thus, the selected 7 compounds having high aroma intensities contributed to the high similarity of aroma quality to the target oil. Odor detection thresholds of 10 chemicals that have high Lod values were comparably determined in water and in model oils at 329 ppm by using an omission test and a cumulative test. Consequently, the odor detection threshold of geranial in the 329 ppm Oilmode110 was 2.86 ppm and the change of the value was 30 fold higher than that in water and the smallest change among other nine compounds. So, the greatest contast in aroma quality of geranial against the aroma of the model oil was proved. The important contribution of geranial to lemon aroma was attributed to the relative immutableness of the odor threshold between water and model oil mixture.