Optimization of ultrasound probe assisted extraction for PKM1 moringa seed oil

Moringa seed oil (MSO) was extracted from moringa seed powder (MSP) us- ing Soxhlet and ultrasound probe-assisted extraction (UPAE) methods. The process conditions for maximizing oil extraction were optimized using re- sponse surface methodology (RSM). The independent variables were 40- 60% ultrasound amplitude, 25-35 min of extraction time, and 1:10-1:20 of solvent-solute ratio for UPAE. The maximum oil yield obtained from the two extraction methods was 40.3 ± 0.79% for Soxhlet extraction (SE) and 36.32 ± 0.44% for UPAE. The process conditions for maximum extraction yield were 60% ultrasound amplitude, 29 min extraction time, and 1:19 of solvent-solute ratio for UPAE and at 60 °C of temperature, 6 h extraction time, and 300 mL of solvent for SE. The optimized extraction process has an oil recovery rate of 90.12% of the total oil content, with an iodine value of 69.18 ± 0.56 g I2/100 g, an acid value of 2.55 ± 0.02 mg KOH/g, and a peroxide value of 1.07 ± 0.02 meq O2/Kg. The physical characteristics of MSO included a refractive index of 1.467±0.03, a specific gravity of 0.92 ± 0.01, a pH of 6.12 ± 0.09, and colour values of 65.77 ± 0.34, 0.34 ± 0.01, and 61.2 ± 0.55 for L*, a* and b* respectively. The antioxidant activity and total phenol content (TPC) of UPAE oil were 33.6 ± 0.26% and 40.1 ± 0.67 ?g/mL, respectively.