The endosperm itself comprises two tissues. The outer part is the aleurone layer, which comprises a single layer of cells in wheat. The aleurone cells have thick walls (and hence high dietary fiber), contain storage lipids (i.e., triacylglycerol) and globulin storage proteins, and are rich in minerals, vitamins, and phytochemicals (micronutrients).
Roughly two thirds (66%) of lipids are contained in the germ, 15% are in the bran (particularly in the aleuronic layer), and about 20% are distributed in the endosperm, partly within the starch granules.
Lipid content, lipid classes and fatty acid levels in wheat kernels depend on a set of factors, some of which are genetic, such as species and variety, whereas others depend on the environment and are related to pedoclimatic conditions, agronomic practices and maturity level.
The majority of the lipids in wheat are fatty acid (FA) esters of glycerol, and the remainder include free (unesterified) fatty acids (FFA) and several types of sterol-based lipids and glycosphingolipids.
Traditional methods of lipid analysis such as thin layer chromatography are limited in their ability to identify and quantify specific lipid molecular species. Latest techniques using sensitive mass spectrometry-based high throughput methods have allowed the detailed and systematic characterization of lipids.
Lipid content in wheat
