Gastrointestinal and colonic in vitro bioaccessibility of γ-aminobutiric acid (GABA) and phenolic compounds from novel fermented sorghum food

Abstract

Effect of lactic acid bacteria fermentation on γ-aminobutiric acid (GABA) and phenolic compounds during the development of red and white sorghum fermented products (RS and WS, respectively) with malted sorghum flour added to each formulation was evaluated. Moreover, intestinal and colonic bioaccessibility of bioactive compounds (IB and CB, respectively) were estimated. Lactic acid fermentation increased significantly (p < 0.05) GABA content in RS and WS (20 and 30%, respectively). Intestinal bioaccessibility of GABA was ~30% for both products. Lactic acid fermentation modified the phenolic acid content differently in the two products. In RS, the free form of ρ-coumaric acid increased, while caffeic, ferulic, and sinapic acid contents decreased. However, WS experienced an increase in the contents of the free ρ-coumaric and sinapic acids. The range of phenolic compound IB and CB was from 1.2 to 54.9%, depending on the product and phenolic acid evaluated. Gallic acid was the most dialyzed phenolic acid at intestinal and colonic levels. The total IB and CB of phenolic compounds was 21 and 6% for RS, and 28% and 4% for WS, respectively.