Vacuum evaporation and nitrogen-assisted deodorization affects the antioxidant capacity in the olein fraction of red palm oil and its emulsion products

Abstract

Background: Deodorization of the olein fraction of red palm oil (OFRP) determines not only the taste of a multivitamin emulsion but also its antioxidant capacity. The emulsion product was formulated from OFRP, pumpkin juice (PJ), and dragon fruit juice (DFJ). This study aimed to optimize vacuum evaporation and nitrogen-assisted deodorizations of OFRP, observing levels of β-carotene, α-tocopherol, inhibition percentage of ABTS reduction, and ferric reducing antioxidant power (FRAP) activity. Methods: The deodorizations observed were vacuum evaporation in four conditions: (1) 90°C, 80±5 mmHg, (2) 100°C, 80±5 mmHg, (3) 90°C, 100±5 mmHg, (4) 100°C, 100±5 mmHg, and nitrogen-assisted in two flow durations: (1) 15 min and (2) 30 min. β-carotene, α-tocopherol, and butylated hydroxytoluene (BHT) were employed as standards. Results: The deodorized OFRP had fewer than 2% free fatty acids (FFA), lower than 3% peroxide value (PV), and lower than 4% acidic value (AV). Fluctuations of the β-carotene and α-tocopherol concentrations were observed in the deodorized OFRP. The final emulsion product had β-carotene of 259.9±1.4 to 271.7±2.4 ppm and α-tocopherol of 36.36±0.20 to 39.12±0.20 ppm. The total betacyanin of the emulsions were ±25% than DFJ. The emulsions had 22.93 to 32.11% of ABTS reduction inhibitory activity of the BHT activity and FRAP activity of 16.54±0.19 to 17.69±0.67 mM FeSO4•7H2O. Conclusions: The best vacuum evaporation optimized at 90 °C, 100±5 mmHg, 60 RPM for 1 hour. The best nitrogen-assisted deodorization was at 85±3°C and 1 l/minute of nitrogen for 15 minutes. The deodorization process affected the antioxidant activity of OFRP and emulsions.