Changes in enzymatic activity, technological quality and gamma-aminobutyric acid (GABA) content of wheat flour as affected by germination

Abstract

The effects of wheat with pre-harvest sprouting (PHS) in the field, and 24, 48 and 72 h in the laboratory-induced germination (IG) were investigated by enzymatic activity, γ-aminobutyric acid (GABA) content, physicochemical, rheological and baking properties. Germination increased the amylolytic activities but did not affect the proteolytic activity. The damaged starch and gluten contents differed between the IGs and PHS flours. By alveography, balanced gluten presented more tenacity with germination increasing. The reduction of farinography values (water absorption, development time and stability), Mixolab parameters (starch gelatinization-C3, resistance amylase-C4 and starch retrogradation-C5) and pasting properties (peak viscosity, breakdown, setback and final viscosity) of germinated flours showed a dough weakening and the capacity for reduction of starch gelatinization. Bread specific volume, firmness, color and bread GABA content were increased in both IGs and PHS flours as compared to non-germinated flour. The germination caused a reduction in gluten strength and protein weakening in the mixing properties. However, it caused an increase in bread volume. There was an increase in the GABA content in flours and bread due to germination.