Effect of organic and conventional farming system on the total phenolic content and antioxidant activity of oats and barley grains

Oats. Total phenolic content (TPC) and radical scavenging activity was higher in hull-less oat varieties cv Stendes Emilija and cv Bikini compare to other tested varieties regardless farming system. However, part of oat varieties showed significantly higher content of tested parameters under organic farming conditions than under conventional farming conditions. There was also found significant difference in TPC and radical scavenging activity for all tested varieties across environments (the field experiments were located at four climatically different locations). Barley. The highest TPC and radical scavenging activity was in grains of hulled barley variety cv Tyra and hull-less barley variety cv Pihl. There was no measured significant difference between farming systems in general, but there was found significant interaction between genotype and farming system. For barley varieties environment and genotype interaction was also stronger pronounced than for oat varieties, except of 2,2′-azino-bis 3-ethylbenz-thiazoline-6-sulfonic acid (ABTS) scavenging activity that was significantly higher in all barley grain samples grown in Priekuli (Latvia)