Parameters affecting oil extraction from rambutan (Nephelium lappaceum L.) seed

Rambutan (Nephelium lappaceum L.) seed is commonly discarded as waste. This seed contains abundant fat that is a valuable source for vegetable oil production. To utilize this seed as a potential oil source for the human diet, this research investigated some technical variables in solvent extraction affecting the yield and quality of vegetable oil. The present research focused on the effect of particle seed size (48-28 mesh sieve), mixture of ethanol/ethyl acetate (1/1, 2/1, 3/1, 1/2, 1/3), solvent to solid ratio (5/1, 6/1, 7/1, 8/1, 9/1), extraction temperature (40-60 degrees C) and extraction time (30-90 min). Results showed that rambutan seed should be finely ground to 35 mesh sieve, soaked with ethanol/ethyl acetate (3/1, v/v) for 30 min, solvent/material ratio (7/1, v/w), extraction temperature (50 degrees C) in 60, 75, 90 min to obtain the high recovery efficiency (95.70 +/- 0.01 %) and medium antioxidant potential (total phenolic content: 14.97 +/- 0.01 mg GAE/g, total carotenoid content: 109.58 +/- 0.02 mg/kg); the low percentage of inhibition to radical DPPH (20.45 +/- 0.00 mg/ml), low peroxide value (1.49 +/- 0.03 mEq/kg), acid value (1.39 +/- 0.02 mg KOH/gm), iodine value (18.27 +/- 0.00 gm/100 gm), saponification value (86.15 +/- 0.03 mg KOH/gm). Comparing to TCVN 7597: 2013, the extracted rambutan seed oil had oxidative indicators within the acceptable limit. This rambutan seed oil would be a potential ingredient for cosmetic and personal health care industries.