Differences of some chemicals and physical properties of winter wheat grain of mealy and vitreous appearance

Abstract

Many wheat species and cultivars, independent of genetic markers of hardness, can produce grain with a vitreous, mealy or mixed appearance. This study analyzed selected chemical and physical differences between kernels with a vitreous and mealy appearance, hand-picked from grain of four winter wheat cultivars cultivated in Poland. Separated fractions were examined for protein content and composition, friabilin presence, carotenoids and total phenolic compounds content, specific kernel density, hardness, as well as kernel surface color. It was found that the ratio of vitreous kernels in the cultivars ranged from 39.18% to 76.28%. Vitreous kernels were darker, slightly heavier and harder than mealy kernels. Additionally, these kernels were more abundant in proteins (an average increase of 2.13%, with variation among cultivars from 0.71% to 2.89%). This type of kernels was also richer in phenolic compounds (on average by 4.02%) and less abundant in carotenoids (on average by 4.53%). Mealy (softer) kernels fractured to a finer flour.Keywords: endosperm vitreousness, mealiness, gluten proteins, kernel density, hardness IntroductionWheat cultivars produce grain in which fully vitreous and mealy, or kernels with mixed endosperm structure exist (Horrobin et al. 2003). So-called "piebald" or "yellow berry" kernels can occur in both durum and hexaploid wheat, with mealy and vitreous zones in a sharply-defined area (Dexter et al. 1989). Evers and Bechtel (1988) explained mealy (starchy, chalky, opaque, soft) endosperm as a result of light scattering at the air-starch and air-protein interfaces. Later studies showed that vitreousness is related to the endosperm microstructure (Greffeuille et al. 2006) as well as to kernel color and its mechanical properties (Peterson et al. 2001;Konopka et al. 2005). Soft endosperm is usually linked with a chalky-opaque appearance, and hard endosperm is linked with a glassy-vitreous appearance. Although the vitreousness of endosperm tissue is more typical of hard wheat, 0133-3720/$20.00 © 2015 Akadémiai Kiadó, Budapest * Corresponding author; E-mail: m.tanska@uwm.edu.pl Cereal Research Communications 43(3), pp. 470-480 (2015) DOI: 10.1556/CRC.2014.0048 First published online 21 April 2015 soft wheat cultivars may also produce cohesive hard sections. Morris et al. (2008) found large variations in endosperm microstructure from kernel-to-kernel within pure cultivars of soft, hard and durum wheats. Such variability can also be affected by the vegetation conditions, especially by fertilization (Samson et al. 2005) and climate (Evers and Bechtel 1988). For example, when a soft cultivar of wheat is grown under optimum conditions, it produces vitreous kernels and, in contrast, many hard types of wheat produce opaque/mealy kernels (Pasha et al. 2010). Kernel vitreousness has been found to generally increase with nitrogen fertilization supply (Farm Facts 1997) and can be declined by damp conditions before grain harvest (Sandhu et al. 2009).It was initially thought that starchy and vitreous zone...

Ruminal degradation and estimated energy and protein values for ruminants of Durum wheat varieties grown in three locations

“…Studies of maize grains have found negative correlations between ruminal degradation and vitreosity, hardness, and kernel density (Correa, 2002; Philippeau & Michalet‐Doreau, 1997; Seifried, 2016). Although notable variation in vitreousness has been reported in soft wheat grains (Konopka, Tańska, & Konopka, 2015), reports on the effects of soft wheat grain hardness on ruminal degradation rate are contradictory (Swan, Bowman, Martin, & Giroux, 2006; Yang, Xu, Zhao, Chen, & McAllister, 2014). The impact of grain hardness on ruminal degradation has not been studied in Durum wheat.…”