Antioxidant Activity in Relationship to Phenolic Content of Diverse Food Barley Genotypes

The antioxidant activity and phenolic composition of 21 mostly hull-less food barley of diverse origin were determined. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide radicals scavenging capacity assays were used to measure antioxidant activity. A photochemi- luminescence technique was used to measure water (ACW) and lipid (ACL) soluble substances. The DPPH radical scavenging capacities of the samples were significantly different (p<0.05), ranging between 13 and 27%. Significant differences existed in the ACW and ACL values. The total phenolic contents were determined using the Folin-Ciocalteu method; values ranged from 2,672 to 3,947 mu g ferulic acid equivalents /g of barley. Tannin contents determined using the vanillin HCl method were significantly different and varied between 36 and 58 mu g catechin equivalents /g of barley. Two hulless genotypes Peru 45, and Ex87xCI 19973 displayed consistently high values of the antioxidant parameters and can be used as antioxidant rich food ingredients. Peru 16, a genotype which had an intact hull that was removed prior to analysis also displayed good antioxidant properties. Due to the difficulty involved in processing, Peru 16 will have to be developed into a hull-less genotype through breeding before adoption for food use. Lack of correlation between tannin and total phenolic contents warrants the need for more detailed chemical analyses and evaluation of functional properties of phenolic compounds of diverse barley materials.