Evaluation of Aroma-Active Compounds in Pontianak Orange Peel Oil (Citrus nobilis Lour. Var. microcarpa Hassk.) by Gas Chromatography-Olfactometry, Aroma Reconstitution, and Omission Test

The aroma-active compounds of Pontianak orange peel oil (Citrus nobilis Lour. var. microcarpa Hassk.) were characterized by using gas chromatography-olfactometry (GC-O) and aroma extract dilution analysis (AEDA) techniques. Forty-one compounds were found to be aroma-active, which were mainly dominated by saturated and unsaturated aldehydes. The flavor dilution (FD) factor was within the range of 2-2048, and compounds having the highest FD factor were alpha-pinene, beta-pinene, linalool, and 2-methoxy-3-(2-methylpropyl) pyrazine, including a few unknown compounds. On the basis of GC-O results, odor activity value (OAV) and relative flavor activity (RFA) were determined for aroma model reconstitution. These resembled the original aroma of the peel oil for the green, fatty, fresh, peely, floral, and tarry attributes, with the model solution derived from OAV being the closest to Pontianak oil. Omission tests were carried out to verify the significance of (Z)-5-dodecenal and 1-phenylethyl mercaptan as key compounds in the aroma of Pontianak orange peel oil.