Selective extraction of polar lipids of mango kernel using Supercritical Carbon dioxide (SC-CO₂) extraction: Process optimization of extract yield/phosphorous content and economic evaluation

Lipids are biomolecules extracted from plant sources and plant residues and have a beneficial role in various food, nutrition and medical applications. Supercritical carbon-dioxide as an advanced high-pressure technology which increases the productivity and has negligible environmental impact is employed for the selective extraction of polar lipids from the lipid matrix in mango kernel for the first time. The process parameters affecting the extraction such as pressure, temperature and the flow rate of CO₂ are ranged in the intervals of 30-50 MPa, 40-60 °C and 10-30 g min^-1, respectively. Optimization using Box Behnken design obtained the highest yield of 3.38% at 40 °C, 50 MPa and 30 g min^-1. The phosphorous content was evaluated to understand the behaviour of polar lipids extraction at higher pressures. The study showed the effect of process parameters having significant influence on polarity and solvating capacity of CO₂ which enabled for the extraction of polar lipids adding value to the mango kernel converting waste into valuable industrial products. The economic evaluation estimates the return on investment of a plant processing 3000 tons of mango kernel per year to account net present value (NPV) almost five times higher than the investment expenses and the payback period is under 4 years.