Effect of thermal processing on antioxidant power and thiosulfinate content in Brussels sprouts juices

The aim of this study was to elucidate the influence of thermal processing at 22-95°C on the antioxidant ability of Brussels sprouts juice and its thiosulfinate content. The antioxidant power was determined by FRAP, Folin-Ciocalteu and DPPH radical scavenging methods. Thiosulfinate concentration was assayed by Han's procedure. It was shown that the increase of processing temperature decreased of the antioxidant ability determined by Folin-Ciocalteu method. However, FRAP and DPPH scavenging showed increase by 20% of the antioxidant power in the final heating step (95°C). The increasing processing temperature resulted in decreasing thiosulfinate concentration until the total loss. This proved that the thiosulfinate present in Brussels sprouts juice is thermolabile compound (not resistant for high temperature). The total loss of the thiosulfinate in high temperature did not reflect the change in antioxidant power. This fact indicated that there was no impact of the thiosulfinate on antioxidant abilities of Brussels sprouts juice or the impact was insignificant among the abundance of other antioxidants. The results showed a good correlation between FRAP and DPPH assays of antioxidant power determination in contrast to correlation with the data of Folin-Ciocalteu procedure.