a b s t r a c t
Nine red and three black rice varieties from Thailand, China and Sri Lanka were analysed to determine
their proximate composition and their physicochemical and antioxidant properties. Four groups of rice
varieties with different amylose contents were identified. Cyanidin 3-glucoside and peonoidin 3-glucoside
were confirmed as the dominant anthocyanins in black rice varieties with contents ranging from
19.4 to 140.8 mg/100 g DM and 11.1–12.8 mg/100 g DM, respectively. Total phenolic content (TPC) differed
significantly between the varieties, but not between the colours. Highest TPC was found in the
red Thai rice Bahng Gawk (BG) with 691 FA equivalent mg/100 g DM, which showed as well the highest
antioxidant properties. In red varieties, the major phenolic acids in the free form were ferulic, protocatechuic
and vanillic acid, whereas in black varieties protocatechuic acid was dominant followed by
vanillic and ferulic acid. In the bound form, ferulic acid was predominant in both colours, where contents
differed significantly, followed by p-coumaric and vanillic acid. The antioxidative capacity did not differ
significantly between both colours but amongst genotypes. Antioxidant capacity of rice varieties ranged
within 0.9–8.1 mmol Fe(II)/100 g DM for FRAP and 2.1–12.3 mmol TEAC/100 g DM. DPPH scavenging
ability ranged from 13.0% to 76.4% remaining DPPH