Impact of Rising Temperature in the Deposition Patterns of Bioactive Compounds in Field Grown Food Barley Grains

Abstract

High temperatures at the end of the season are frequent under Mediterranean conditions, affecting final grain quality. This study determined the deposition patterns throughout grain filling of dry matter, dietary fiber, phenolic compounds and antioxidant capacity for four barley genotypes under two contrasting temperatures. Deposition pattern for dietary fiber followed that of grain weight. Genotypic differences for duration were more significant than for rate. Anthocyanins followed a second-degree polynomial pattern, reaching a maximum before grain maturation. Free and bound phenols decreased as grain developed, suggesting that they are synthesized in early stages. Rate of bound phenols deposition was more sensitive to genotypic changes. Overall, antioxidant capacity decreased over time; the decay being less steep under stress for all genotypes. Heat stress negatively affected grain weight. It did not alter the profile of β-glucans and arabinoxylans deposition but positively changed the accumulation of some phenolic compounds, increasing the antioxidant capacity differentially across genotypes. These results support the growing of food barley in high-temperature stress-prone areas, as some bioactive compound and antioxidant capacity will increase, regardless of the smaller grain size. Moreover, if a market develops for food-barley ingredients, early harvesting of non-mature grain to maximize antioxidant capacity should be considered.

Dissecting the resilience of barley genotypes under multiple adverse environmental conditions

“…The results of ANOVA in this investigation indicated that both genotype and environment had a highly significant effect on all the traits examined. These findings were in agreement with those previously reported [ 27 ]. Such findings reveal that different genetic makeup of these barley genotypes can have varying inherent characteristics that affect their performance.…”

Phenolic Profile Dynamics during Grain Development in Hull-Less Food Barley Genotypes with Varying Grain Colors

“…Kohyama et al [45] associated this reduction, occurring just before harvest, in purple hull-less varieties with processes such as degradation, diacylation, or insolubilization of anthocyanins. Bustos et al [46] reported a similar pattern in total anthocyanins in purple wheat, while Martínez-Subirà et al [20] observed the same trend barley genotypes. In both cases, the peak content of anthocyanins was reached at physiological maturity, followed by a significant decrease until harvest.…”

“…Previous researchers found that immature corn seeds possess high concentrations of reducing sugars, high protein contents with biological activity, and higher antioxidant activity than mature grains [19]. For barley, previous studies showed that total phenolic content gradually decreases throughout grain development, accompanied by a decline in antioxidant capacity [20]. However, comprehensive investigations into the dynamic changes of specific PCs such as phenolic acids, flavan-3-ols, flavones, and anthocyanins, and their corresponding antioxidant activities during the barley grain development are lacking.…”

Does Plant Breeding for Antioxidant-Rich Foods Have an Impact on Human Health?

“…Biscuits containing different proportions of whole flour and pearling fractions from a purple hull-less barley genotype showed high in vitro antioxidant capacity [103]. Interestingly, genotypic differences influence the content of bioactive compounds more than the environment, and heat stress at the end of the growing season increased the phenolic compounds and their antioxidant capacity [104].…”