Chemical compounds distribution in wheat seeds and the effect of parboiling on chemical and technological properties of einkorn (Triticum monococum L.)

A fractionate analysis of chemical compounds in kernels of einkorn (Triticum monococcum L. subsp. monococcum) and bread wheat (Triticum aestivum L. ssp. aestivum) accessions showed that the germ fraction had the highest concentration of protein, lutein, -tocopherol, -tocopherol and total tocols. Ash, -tocotrienol and -tocotrienol levels were highest in the bran fraction, although significant quantities were detected also in the germ and, for tocotrienols, in the endosperm. Notwithstanding the lower concentrations, the endosperm contributed most protein and lutein, as well as one-third of tocotrienols to the whole kernel; this suggests that, after the milling process, the white flour still retains most of the nutritional value of the whole kernel. The influence of kernel parboiling on compounds distribution as well as on chemical and technological flour properties was assessed by steaming, under different time/temperature conditions, seeds of five einkorn accessions and one bread wheat control. Ash, protein, lutein, tocols and -amylase contents, SDS sedimentation volume and gelatinisation parameters were measured on the resulting flours. Furosine, a heat damage marker, was also assessed. Most of the traits analysed were influenced by the parboilisation treatments. Lutein, tocols and -amylase diminished after steaming; SDS sedimentation volumes and most gelatinisation parameters also decreased, whereas gelatinisation temperatures and furosine contents increased. The changes were stronger under more drastic steaming conditions, although treatments x genotype influence was sometimes detected. Steaming induced migration of lutein and tocopherols from the bran and the germ fractions to the kernel endosperm.