Dry Fractionation Approach in Concentrating Tocopherols and Tocotrienols from Palm Fatty Acid Distillate: A Green Pretreatment Process for Vitamin E Extraction

Optimization of Vitamin E Extraction from Rice Bran Oil Deodorizer Distillate using Response Surface Methodology

Rice bran oil deodorizer distillate (RBODD) is the low valuable secondary product of refinery rice bran oil. However, RBODD contains bioactive compounds such as vitamin E, gamma-oryzanols, and phytosterols. To increase value of vitamin E obtained from underutilized product, tocopherols and tocotrienols were extracted from RBODD using ethanol followed by a freezing step. The response surface method (RSM) is known as a potential tool for optimizing processing parameters in order to save time, energy, and chemical material. In current study, vitamin E extract (VEE) was extracted using ethanol and response surface method (RSM) was employed to investigate the optimum condition. The ratio of RBODD: ethanol (1:5, 1:10, and 1:15) and the incubation temperature (0, -20, and -40℃) of vitamin E extraction were used to design the experiment using a central composite design (CCD). Once the optimization process was completed, the RSM was executed using the following 5 responses simultaneously: VEET3, VEEToc, VEETot, RecoveryVEE, and YieldVEE. Results showed that values of each parameter were VEET3 (10.69-89.60 mg/g), VEEToc (2.85-23.37 mg/g), VEETot (13.53-112.97mg/g), RecoveryVEE (16.15-134.76%), and YieldVEE (12.64-44.48%). All model predictions were significant (p-value < 0.05), with non-significant lack of fit (> 0.05). In addition, the values of R2 and R2(Adj) of model were in the range of 0.922-0.988 and 0.893-0.982, respectively. According to these findings, response values were associated with RBODD:ethanol ratio and the incubation temperature. The ratio 1:9.5 (RBODD: Ethanol) and incubation temperature at -26.5 ℃ provided the optimal condition for vitamin E extraction from RBODD. At this optimum condition, it was determined that the predicted responses for VEET3, VEEToc, VEETot, RecoveryVEE, and YieldVEE were 81.87 mg/g, 23.70 mg/g, 103.64 mg/g, 123.63 %, and 20.05%, respectively. The obtained product with high content of tocopherol and tocotrienol can be used as ingredient in food as well as pharmaceutical applications.

Separation of tocol (tocopherol & tocotrienol) and phytosterols from palm fatty acid distillate by saponification and purification by low temperature solvent crystallization

The tocotrienols (T3) are the vitamin E family members with excellent antioxidant properties and prevent autocatalytic lipid peroxidation. Palm Fatty Acid Distillate (PFAD) is a volatile organic material obtained during palm oil refining and consists of tocol (α-tocopherol/T, α, γ, β, and δ- tocotrienol/T3) up to 0.8% and represents a potential source for recovering these valuable compounds. Various methods have been studied to extract vitamin E; however, only a few are commercially available. To fulfil the need for technology for recovering these minor components, leaching the tocotrienol from solidified PFAD was carried out. In this study, the fatty acid of PFAD was saponified using NaHCO₃/Ca(OH)₂ and extracted the unsaponifiable fraction using solvent. Further, fraction was purified by low temperature solvent based crystallization using hexane at 5 ± 1.0 °C for 24 h and removed sterol. The best determined parameters like reaction time (30 min), the ratio of PFAD to Ca(OH)₂ (1,w/w), reaction temperature (30 °C) and stirring speed 300 rpm were yielded up to 98.6% fatty acid conversion to calcium soap and extraction with hexane obtained higher concentration of tocol (28.1%). The sterol separated from the tocol rich fraction by low temperature solvent crystallization contains up to 37.1% of phytosterol (β-sitosterol) concentration.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-022-05402-7.