Effect of genotype and crop management systems on the content of antioxidants in hulless and covered spring barley

This paper deals with studies of the content of some antioxidants in barley (Hordeum vulgare L.), which is one of the major cereal species with extensive application in food products with increased nutritional value. We studied the effect of genotype and environment on the content of alpha-tocopherol and total polyphenol content in grain and grain oil and phenolic compounds in grain of two covered and four hulless barley genotypes grown under one organic and three conventional management systems with increasing agrochemical input during 2011-2012. alpha-Tocopherol in grain and oil during both years ranged between 1.49-14.51 mg kg(-1) and 9.24-88.32 mg 100 g(-1), respectively, with particularly low values in comparatively cooler and wetter year 2012. Total polyphenol content in grain and oil ranged between 81.66-140.13 and 0.19-8.52 mg gallic acid equivalents (GAE) 100 g(-1), respectively. We identified 13 phenolic compounds with the highest concentration for ferulic acid, followed by p-coumaric and syringic acids. No clear significant effect of crop management systems on the content of antioxidants was found. Conditions of the growing year had the greatest effect on the content of alpha-tocopherol, total polyphenol content and most phenolic compounds. alpha-Tocopherol content in barley grain and oil was generally higher under conventional management with higher input level; higher mean content was found for some hulless genotypes, although there was no significant difference between hulless and covered types. Higher total polyphenol content in grain was generally found under organic and lower input conventional management systems. Total polyphenol content was higher for covered barley genotypes in comparison to hulless genotypes. Higher total polyphenol content concentration in oil was found under medium intensive conventional management with covered genotypes being superior in 2011. The content of most phenolic compounds tended to increase with decrease of agrochemical input level and higher content was in covered than in hulless genotypes with some exceptions.