The effect of alternative solvents to n-hexane on the green extraction of Litsea cubeba kernel oils as new oil sources

Litsea cubeba (LC) is an indigenous industrial crop in China with fruits possessing interesting essential oil content of 3-5%, which production leads to a large number of kernels as wastes. In this study, the performance of four alternative solvents on the extraction of LC kernel oils was firstly evaluated in comparison with n-hexane as the reference solvent. Regardless of the solvent used, all extracted oils were quantitatively and qualitatively analyzed, where green solvents (dimethyl carbonate-DMC and cyclopentyl methyl ether-CPME) were preferred to alcoholic solvents (ethanol and isopropanol) considering their higher extraction yields and similar acylglycerol and fatty acid compositions to oils extracted by n-hexane. Interestingly, micronutrients in oils extracted by green solvents were quantified much higher than that extracted by n-hexane. Apart from common physicochemical properties measured, Hansen solubility parameter and antioxidant activity in vitro were also studied to make a more comprehensive profile for solvent effects and oil functionality. The results indicated that CPME could be the optimal alternative solvent to n-hexane with comparable extractability and selectivity in the green extraction of LC kernel oils as a new promising natural plant oil resource.