Development of a gluten-free whole grain flour by combining soaking and high hydrostatic pressure treatments for enhancing functional, nutritional and bioactive properties

Single and double high hydrostatic pressure (HHP) cycles combined with soaking pre-treatment were applied on buckwheat (BW) whole-grain to enhance the nutritional, functional and bioactive properties of BW flour. Results showed modifications in the microstructure of pre-soaked and HHP treated samples which were associated with the appearance of disruptions on the surface of the starch granules. Combined treatments significantly (p < 0.05) affected the ability of the flours to produce a stable emulsion or foam layer. These treatments also resulted in a significant decrease (p < 0.05) in the gelatinization enthalpy and in the peak viscosity of the flours, while increasing their stability versus heating and shearing. Combined treatments also enhanced significantly (p < 0.05) the antioxidant properties with an increase of phenol content from 311 mg GAE/100g in native flour to 361 and 347 mg GAE/100g in pre-soaked and HHP-treated samples at single and double cycle, respectively. More-over, those samples also exhibited higher minerals retention than un-soaked ones. The data obtained from this study demonstrated the efficiency of the application of combined soaking and HHP treatments on BW grains to enhance the nutritional and functional response of resulting BW flours providing a value-added ingredient with interest in the gluten-free baked goods industry.