Changes in lipid components during the development of the french bean seed (Phaseolus vulgaris)

Changes in lipid classes, fatty acid composition and distribution have been monitored during the germination, development and maturation of the French bean seed Phaseolus vulgaris. A lipase activity profile over time was also determined. Ungerminated seeds contained high levels of triglycerides and free fatty acids, but low levels of polar lipids, monoglycerides, and diglycerides. Five days after germination there was a decrease in the quantity of triglycerides and free fatty acids and a concomitant increase in the levels of monoglycerides, diglycerides, and polar lipids. As development and maturation progressed, triglycerides increased substantially at the expense of mono- and diglycerides. Ungerminated seeds contained high levels of C₂₀-C₂₂ fatty acids which decreased after germination with a concomitant increase in C₁₆-C₁₈ unsaturated fatty acids. A study of the fatty acid distribution among the different classes of lipids demonstrated that 55% of the unsaturated fatty acids in the ungerminated seeds were present in the triglycerides, whereas the remainder were distributed among the mono- and diglycerides as well the other lipid classes (free fatty acids, polar lipid, and sterols). Five days after germination, the majority of these unsaturated fatty acids were found in the glyceride form. Overall the lipid classes, fatty acid composition and distribution changes during development and maturation of the French bean seed indicated that it shares many of the characteristics of soya bean development.