Impact of fermentation on in vitro bioaccessibility of phenolic compounds of tef injera

Simulated static in vitro digestion of tef injeras, sampled after different fermentation times, was performed to measure the dialyzable (D) and soluble nondialyzable total phenolic (TPC), total flavonoid contents (TFC), and their total antioxidants using ABTS, DPPH and FRAP assays. The %TPC and %TFC of D and SND fractions of the in vitro digested injeras were in the range of 2-3%, 5-10%, 1-3%, 4-9%, 18-51%, respectively. The %ABTS and %DPPH radical scavenging capacities and %FRAP in the D and SND fractions ranged from 41 to 94%, 0.02-0.62%, 0.62-2%, and 8-16%, respectively. The absolute TFC of the D and SND fractions decreased as the fermentation increased from 0 to 120 h. No clear pattern in the absolute TPC, DPPH radical scavenging capacity and FRAP in the D and SND fractions was observed among different fermentation times, while the absolute ABTS and %ABTS radical scavenging capacities of the D and SND increased with increasing fermentation times.