The distribution of lipids in the germ, endosperm, pericarp and tip cap of amylomaize, LG‐11 hybrid maize and waxy maize

Abstract

AbstractThe quantitative distribution of 23 acyl lipid classes and unsaponifiable matter in kernels of amylomaize, LG‐11 hybrid maize and waxy maize is described. LG‐11 and waxy maize were normal (oil content) varieties, containing 4.9% and 5.1% lipid, respectively, while amylomaize (9.3% lipid) was a high oil variety. The distribution of kernel lipids was 76–83% in germ, 1–2% in pericarp, 1% in tip cap, 1–11% in starch, and 13–15% in aleurone plus the nonstarch fraction of the starchy endosperm. Germ contained 39–47% lipid, which was nostly triglyceride (TG), with some steryl esters (SE) and diglycerides (DG), and small amounts of glycolipids (GL) and phospholipids (PL). Aleurone lipids appeared to be TG with some free fatty acids (FFA) and SE. The other nonstarch lipids in starchy endosperm were FFA with very small amounts of SE, DG, GL and PL. The starches had a little surface lipid (FFA) and true (internal) starch lipid (FFA, lyso‐PL) in quantities roughly related to amylose content (amylomaize =ca. 73% amylose, 1.0% lipid; LG‐11=23% amylose, 0.7% lipid; waxy maize =<5% amylose, 0.2% lipid). Pericarp lipids (0.8–2.5%) were mainly unsaponifiable matter, the acyl lipids being TG, SE, DG and FFA. Tip cap lipids (2.5–2.9%) had more TG, GL and PL than pericarp lipids, but were otherwise similar. Pericarp lipids and endosperm nonstarch lipids appeared to have suffered extensive degradation at some time during kernel development or after harvesting, while lipids in starch, germ and tip cap were evidently unaffected. FFA and lyso‐PL are regarded as normal components of maize starch (rather than degradation products) and may occur as amylose inclusion complexes.