Process kinetics, thermodynamics and optimization of oil extraction from the garlic pennycress (Thlaspi alliaceum L.) seeds

Garlic pennycress seed oil (GPSO) was recovered by pressing, Soxhlet extraction, and maceration. All obtained GPSOs are characterized by high viscosity and low iodine value. The oils have a lower content of polyunsaturated fatty acids and a higher content of saturated fatty acids compared to other Brassicaceae plant oils. The most common fatty acids are oleic and linoleic acids (with a content of over 30%) followed by behenic acid (average content of 14.3%). The phenomenological and diffusional kinetic models were reliable for modelling the kinetics of GPSO maceration (mean relative percentage deviations between experimental and modelled oil yields are ± 1.7% and ± 3.5%, respectively). Based on the thermodynamic analysis, the process is endothermic, irreversible, and spontaneous. The GPSO maceration was statistically evaluated, modeled, and optimized using a 3³ full factorial design. The oil yield is affected by extraction temperature, solvent-to-seed ratio, and extraction time, and the most significant factor is extraction temperature. Based on the developed quadratic model, the optimal maceration conditions were determined as follows: extraction temperature 70 °C, solvent-to-seed ratio 10:1 mL/g, and extraction time 10 min.