Characterization of key aroma-active compounds in lychee (Litchi chinensis Sonn.)

Shi Feng ^a,b, Mingyang Huang ^a, Jonathan Henry Crane ^c, Yu Wang ^a,b,*

^a Citrus Research and Education Center, University of Florida, 700 Experiment Station Rd, Lake Alfred, FL 33850, USA

^b Department of Food Science and Human Nutrition, University of Florida, 572 Newell Dr., Gainesville, FL 32611, USA

^c Tropical Research and Education Center, University of Florida, 18905 SW 280 St., Homestead, FL 33031, USA

Volatile compounds in ‘Sweetheart’ lychee were examined using gas chromatography-olfactometry/mass spectrometry (GC-O/MS). Solvent assisted flavor evaporation (SAFE) technique was used to identify the aroma-active compounds in lychee. Further characterization of the most important odorants in ‘Sweetheart’ lychee was achieved using aroma extract dilution analysis (AEDA). Thirty-one key aroma-active odorants were identified in the flavor dilution (FD) factor range of 2–1024. Methional (cooked potato) and geraniol (sweet, floral) exhibited the highest FD factors of 1024 and 512, respectively, these were followed by furaneol (sweet, caramel), nerol (floral, sweet), dimethyl trisulfide (DMTS) (preserved vegetable, sulfury), linalool (floral), (E,Z)-2,6 nonadienal (cucumber) and nerolidol (metalic, sesame oil). Furthermore, the flavor profile of ‘Sweetheart’ lychee was described by sensory analysis. Floral, tropical fruit, peach/apricot and honey were scored with relatively high scores for each aroma attribute. The sweetness rating was the highest score among all the attributes.