| Abstract: | Whole sunflower seeds (Helianthus annuus L.) were exposed to microwaves for 6, 12, 20 or 30 min at a frequency of 2450 MHz. The hulls were then stripped from the seeds. Molecular species and fatty acid distributions of triacylglycerols (TAGs), isolated from total lipids in the hulls, were analyzed by a combination of argentation thin‐layer chromatography (TLC) and gas chromatography. A modified argentation TLC procedure, developed to optimize the separation of the TAGs, provided 10 different groups of TAGs, based on both the degree of unsaturation and the total fatty acid chain‐length. Dilinoleolein (29.5—30.2 wt‐%), trilinolein (18.2—24.2 wt‐%), dilinoleopalmitin and dilinoleostearin (17.0—18.1 wt‐%), palmitoleolinolein and stearoleolinolein (11.4—14.0 wt‐%) and dioleolinolein (7.5—8.6 wt‐%) were the main TAGs detected after microwave roasting. However, roasting caused a significant decrease (p < 0.05), not only in TAG molecular species containing more than four double bonds, but also in the amounts of diene species present in TAGs. These results suggest that microwaves should affect TAGs in the hulls more significantly (p < 0.05) than those in the sunflower kernels. |
