Effects of Germination on Starch Structure and Physicochemical Properties of Highland Barley

Highland barley starch (HBS) holds food industry potential but is limited by its native properties. This study investigated how germination (0-5 days) modifies HBS. Results showed germination reduced the total starch content by 31.17%, protein by 26.19%, and molecular weight but increased surface holes. While the average particle size reduced from 18.39 µm to 17.29 µm. The proportion of amylose relative to total starch increased from 49.55% to 60.39%, whereas the relative proportion of amylopectin decreased from 50.45% to 39.61%. Germination did not change the crystalline pattern of HBS, but the relative crystallinity first increased from 20.05% (0 day) to 23.43% (1 days) and then decreased to 16.80% (5 days), which was consistent with the trend of gelatinization enthalpy (ΔH) that first rose from 7.78 J/g to 11.08 J/g and then dropped to 7.94 J/g. The peak viscosity (PV), trough viscosity (TV), final viscosity (FV), and setback value (SB) of HBS all decreased significantly: PV decreased from 1876 cP to 972 cP, TV from 1382 cP to 218 cP, FV from 1956 cP to 390 cP, and SB from 574 cP to 172 cP after 5 days of germination, while the breakdown value (BD) increased from 494 cP to 754 cP. Functional properties including water solubility index (WSI), swelling power (SP), and oil absorption capacity (OAC) improved markedly. These findings demonstrate germination effectively tailors HBS structure and functionality, providing a green modification strategy for enhanced food applications.