Comparative Study on Breadmaking Quality of Normoxia- and Hypoxia-germinated Wheat: Evolution of γ-Aminobutyric Acid, Starch Gelatinization and Gluten Polymerization during Steamed Bread Making.

To explore breadmaking characteristic of germinated wheat flour, current study focused on the componential evolution throughout steamed bread making process. Hypoxia-germinated wheat (HGW) dough produced the maximum GABA due to high glutamic acid decarboxylase activity during fermentation compared with normoxia-germinated wheat (NGW) and sound wheat (SW). HGW was superior to NGW in terms of rheological properties, and restored the organoleptic characteristics as SW bread. Blocking of α-amylase activity and protein polymerization demonstrated that the decline in pasting and gelation properties was not caused by changes in intrinsic starch and protein properties. Polymerization of α- and γ-gliadin to glutenin was facilitated in germinated-wheat bread, while the crosslinking degree of glutenin-gliadin was suppressed. Compared with NGW bread, more high molecular weight glutenin subunits but less α-gliadin fractions polymerized upon steaming of HGW dough. Results demonstrate that HGW has the great potential to be exploited as a nutritious functional ingredient for wheat-based food.