Effects of germination on total phenolic compounds and radical scavenging activity in hull-less spring cereals and triticale
¹Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, St. Rigas 22, LV-3004 Jelgava, Latvia
²Norwegian Institute of Bioeconomy Research, St. Fredrik A. Dahls 20, Ås, Akershus, NO 1432, Norway
The aim of the current research was to evaluate changes in the content of total phenolic compounds and radical scavenging activity at different germination stages of triticale, hull-less barley, hull-less oats, wheat, and rye. Grain germination was performed for 12, 24, 36 and 48 h at controlled conditions. Ultrasound assisted extraction was used for isolation of total phenolic compounds. For all extracts the total phenolic compounds content, DPPH radical and ABTS+ radical scavenging activity were determined spectrophotometrically. The results of the experiments demonstrated that the highest content of total phenolic compounds and the highest antiradical activity was determined in hull-less barley samples. In all studied grains the content of phenolic compounds increased significantly during soaking and germination process. DPPH radical scavenging activity during germination increased. ABTS+ radical scavenging activity also increased after soaking process and dynamics were cereal type dependent. Pearson’s coefficients between the phenolic compound levels and antioxidant activity taking into account all obtained results were high. Very strong positive correlations between the content of phenolic compounds and antioxidant activity were determined for triticale during germination. Also antioxidant activity determined by both tests correlated with the highest results for barley and oats. The highest content of total phenolic compounds determines the optimum duration of germination to be 24 hours, except rye samples where the highest value was reached only after 48 hours of germination. Shorter time was required to reach the highest values of DPPH radical activity – for wheat rye, and triticale, namely 12 hours.