Total phenols and antioxidant capacity of hull-less barley and hull-less oats
¹Latvia University of Agriculture, Department of Food Technology, Rigas iela 22, LV-3004 Jelgava, Latvia
²Institute of Agricultural Resources and Economics, Zinatnes iela 2, LV-4126 Priekuli, Latvia
³Norwegian Institute of Bioeconomy Research, Fredrik A. St. Dahls 20, 1432 Ås, Norway
Grain products are the main source of carbohydrates but they also contain other bioactive substances such as phenolic compounds. Content of phenolic compounds differ among cereal types, varieties, and farming methods. The aim of the current study was to assess total phenolic content and radical scavenging activity in different oats and barley varieties compared to hulled ones. In the experiment hull-less varieties / lines were analysed: three barley (line ‘GN 03386’, from Norway and ‘Kornelija’, ‘Irbe’ from Latvia) and three oats varieties (‘Bikini’, ‘Nudist’, from Norway and ‘Stendes Emilija,’ from Latvia). One hulled variety of barley and oats from each country was included in the experiment for comparison. For the isolation of phenolic compounds ultrasound assisted extraction was used. For all extracts the total phenol content and DPPH, ABTS+ radical scavenging activity were determined spectrophotometrically. Overall, the highest content of total phenols was detected in hull-less barley samples. The barley variety with the highest content was line ‘GN 03386,’ followed by varieties ‘Kornelija’, ‘Irbe,’ and hulled Norwegian barley variety ‘Tyra’. High DPPH and ABTS+ radical scavenging activity was recorded in barley line ‘GN 03386’. Generally, there was strong correlation between total phenol content and ABTS˙+radical scavenging activity and moderate correlation between total phenol content and DPPH radical scavenging activity. In conclusion, the barley varieties had generally higher content of bioactive substances than oats and the barley line ‘GN 03386’ seems to be one of the best.