Characterization of Volatiles in Rambutan Fruit (Nephelium lappaceum L.)

Area of Science:

• Food Science
• Analytical Chemistry
• Plant Biochemistry

Background:

• Rambutan (Nephelium lappaceum L.) is a tropical fruit native to Southeast Asia.
• The Jitlee cultivar is known for its distinct red skin and desirable sensory characteristics.
• Understanding the volatile profile is crucial for appreciating and potentially enhancing the fruit's aroma.

Purpose of the Study:

• To extract and identify volatile compounds responsible for the aroma of the Jitlee rambutan cultivar.
• To characterize the odor-active compounds using advanced analytical techniques.
• To determine the primary contributors to the overall aroma profile of the fruit.

Main Methods:

• Volatile compounds were extracted using Freon 113 and ethyl acetate solvents.
• Gas chromatography/olfactory (GC/O), chromatography, and spectrometry were employed for isolation and characterization.
• Authentic standards were used for mass spectral, retention index, and odor matching.

Main Results:

• Over 100 volatile compounds were detected by gas chromatography/mass spectrometry (GC/MS).
• Ethyl acetate extraction yielded more polar volatiles and detected more odor-active compounds compared to Freon extraction.
• Key odorants identified include beta-damascenone, ethyl 2-methylbutyrate, and various aldehydes and acids, contributing to fruity, sweet, and fatty-green notes.

Conclusions:

• The exotic aroma of Jitlee rambutan results from an interaction of fruity-sweet and fatty-green odors.
• Specific compounds like beta-damascenone and ethyl 2-methylbutyrate are major contributors to the fruit's characteristic scent.
• Potential contributions from civet-like, sweaty, spicy, and woody notes add complexity to the overall aroma profile.