Total yellow pigment content and oxidative stress level during kernel development of durum wheat

The focus of this research was to determine the effects of cultivar and environment on levels of total yellow pigment content and oxidative stress during grain development and in semolina and pasta. Lipoxygenase activity increased just before and declined after physiological maturity, while change in malondialdehyde content in the kernel mirrored that of yellow pigment and declined with maturity. After grain reached physiological maturity, levels of lipoxygenase activity, malondialdehyde content and yellow pigment content per kernel were lowest in 2011, while polyphenol oxidase activity was lowest in 2010. Lipoxygenase activity and yellow pigment content decreased after milling and processing, whereas malondialdehyde content decreased after milling but increased with processing. No lipoxygenase activity was detected after processing. Stereomicroscopy and scanning electron microscopy were used to observe anatomical and morphological changes that occurred as durum wheat caryopsis progressed from anthesis to final desiccation.