A robust technique for the group classification of the C-13 NMR spectra of natural products from Meliaceae

Rapeseed, soybean and sunflower seeds are used for a comparison of solvent extractions by SFE, ASE, fexIKA and Soxtherm apparatus with the official standard method B-I 5 (87) by the DGF. The optimal extraction parameters for each method are evaluated. The extracts are analysed regarding the composition of tocopherols, as a parameter for mild extraction conditions and the content of free fatty acids and diglycerides, as a parameter for the recovery of more polar lipids. The obtained results for oil content using the optimised methods agree well with the standard method. Differences occur in the results of tocopherol composition and free fatty acid and diglyceride contents. The SFE method shows the highest recovery regarding the tocopherol content. The extraction period by SFE is reduced to about 40 min in contrast to 4 h of the DGF standard method. The other methods also provide considerable time reductions, but showed lower tocopherols and free fatty acid contents.