How does extrusion chage the phenolic profileand impact protein digestibility in sorghum flours?

In this work, the effect of thermoplastic extrusion on the phenolic compounds (PC)profile by UPLC-MSEand on the solubility/polymerization of kafirins by SE-HPLC was evaluated in extruded whole sorghum, with or withouttannins. Free (FPC) and bound (BPC)phenolic compoundswere extracted separately.The characteristics evaluated are antioxidant activity (by the methods DPPH and FRAP),total phenoliccontent(by the methodology involving the Reagent of Folin Ciocalteu), total proanthocyanidinscontent (TPAC) and total flavonoid content (TFC). FPC and BPC ranged from 41.1 to 434.3and 8.2to 283.7mg GAE/100g (db), respectively.DPPH and FRAP analysis showed a strong correlation with TPC (0.99and 0.95, p< 0.05, respectively). TPAC and TFC showthe degradation of tannins in monomeric flavonoids, after extrusion. Globally, 58 FPC and 100 BPC were tentatively identified. PCA biplotindicated a clear distinction between PC profile in flour and extrudate in both genotypes. SE-HPLC showed an increase in protein solubility after extrusion thus it also improves protein digestibility.This work reveals that the extrusion improve the release of BPC, the breakdown of polyphenols and the depolymerization of kafirinsin sorghum grains, promoting theuse of this cereal as a potential functional foodfor humans.CBCP; 5 a 9 out