Optimization of the Extraction Method of Vegetable Oil from Carapa procera Almonds Extracted Using a Hydraulic Press

Abstract

Carapa procera (Meliaceae), known for its traditional therapeutic properties, was the subject of this study focused on optimizing the method of extracting oil from its kernels, a raw material of choice for cosmetic and pharmaceutical industries. Two extraction methods were compared (artisanal extraction and extraction using hydraulic press). The results showed that hydraulic press extraction gives better yields with yields ranging from 22.36 to 29.75%, while artisanal extraction gives yields ranging from 0 to 18.40%. Furthermore, the extraction method has no influence on the physico-chemical properties (acid, peroxide, refraction, and saponification index) of the oil. Nevertheless, it influences the chemical composition of the latter. Since the oil yields obtained by the hydraulic press extraction method were better, this method was chosen for optimization. In order to evaluate the impact of process parameters on oil yield, two experimental designs were implemented : the two-level full factorial as well as Box-Behnken designs, and used  Minitab 21 software for statistical analysis. The statistical analysis confirmed the relevance of the model used in accordance with the high values ​​of the coefficients of determination R² (0.9884) and adjusted R² (0.9651), close to unity, and p values (p<0.05). The results highlighted the   significant influence of two factors on the yield : fermentation duration (A) and pressure (B). The oil yields ranged between 12.40 and 36.94% after optimization. In summary, the optimal conditions for improving yield are : an almond fermentation period of 21 days, a pressure of 300 bars, and a roasting duration of 7.5 minutes. Furthermore, in order for this method to be more profitable, this study recommends removing the shelf-life phase which has a negative influence on the oil yield.