Characterization and Quantification of the Aliphatic Hydrocarbon Fraction during Linseed Development (Linum usitatissimum L.)

Changes in hydrocarbon composition were investigated during maturation of three varieties of linseed (H52, O116, and P129) cultivated in Tunisia. The hydrocarbon fraction of the three linseed oil samples was found to contain mainly n-alkanes and squalene. The greatest decrease of these components occurred between 7 and 21 days after flowering (DAF); thereafter, the changes were slight. At 7 DAF, P129 had a significantly higher level of squalene (27.24 mg/100 g of oil) than H52 (3.36 mg/100 g of oil), but from this date until 21 DAF squalene decreased much more actively in P129, resulting in similar levels in H52 (0.57 mg/100 g of oil) and P129 (0.52 mg/100 g of oil) at full maturity. In three varieties of linseed, 13 n-alkanes were detected ranging from C-22 to C-34 carbon atoms. The n-alkane composition of linseed oil was influenced by the ripening stage of seeds. At 7 DAF, C29 was the most predominant hydrocarbon (19.84 mg/100 g of total oil), followed by C-27 (11.82 mg/100 g) and C-25 (11.28 mg/100 g). C-29 exhibited the most significant decrease from 7 to 21 DAF, as a result C-27 being the most significant n-alkane component for the remainder of the period. At full maturity, the content of total n-alkanes in three varieties of linseed ranged from 4.0 to 4.26 mg/100 g of oil.