Characterization of potent odorants in Thai chempedak fruit (Artocarpus integer Merr.), an exotic fruit of Southeast Asia

Chempedak (Artocarpus integer Merr.) is a native fruit in Malaysia, Indonesia and southern Thailand, and like jackfruit, belongs to the Moraceae family. The characteristic aroma-active components of two chempedak cultivars, Tongtapan and Sainumpung, grown in southern Thailand were analyzed by aroma extract dilution analysis (AEDA) combined with gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). The predominant odorants [with flavor dilution (FD) factors > 9] in both cultivars were 4-hydroxy-2,5-dimethyl-3(2H)-furanone (burnt sugar, sweet), 3-methylbutanal (dark chocolate), methional (cooked potato-like), and 2-acetyl-1-pyrroline (popcorn, jasmine), while ethyl 3-methylbutanoate (fruity) was predominant only in Tongtapan cultivar. Selected positively identified aroma-active compounds were further quantified using stable isotope dilution assays (SIDA) combined with GC-MS. On the basic of the quantitative data and odor thresholds, odor activity values (OAV) were determined. Aroma recombination models and omission models were constructed for both cultivars based on concentrations of odorants with high OAVs and then validated and characterized by sensory studies. Complete aroma recombination models of both chempedak cultivars were reconstituted and characterized by comparison with authentic chempedak fruits. Omission studies were performed to verify the significance of character-impact odorants in both chempedak cultivars. Based on sensory evaluation, 3-methylbutanal, octanal, and 2-acetyl-1-pyrroline were found to be important odorants in the overall aromas of both cultivars, while ethyl 3-methylbutanoate was an additional key odorant in the aroma of the Tongtapan cultivar.