Abstract:

The present work was designed to obtain information on the effect of germination on starch composition and
rheological, gel, thermodynamic and processing properties of brown rice starch. Brown rice starch was extracted at different
stages (0, 24, 48, 72, 96, and 120 h) of germination. The starch rheological properties were examined by a rheometer, the
texture properties of starch gels were analyzed by texture analyzer and changes in thermodynamics and processing properties
of starch during 120 h germination were also investigated. The results showed that the contents of total starch and amylase
decreased over the germination period. With the extension of germination time, the peak values of G’ and G” increased,
denaturation temperature dropped and elasticity and viscosity went up. Germination had different impacts on the texture
properties of starch gels. Gel strength, hardness, springiness, gumminess and chewiness reached a maximum level at 72 h.
Differential scanning calorimetry (DSC) analysis showed that germination had little effect (P > 0.05) on phase transition
temperatures (To, Tp, Tc) of starch, but the gelatinization enthalpy increased and the stability and crystallinity were improved.
Moreover, the emulsification and emulsion stability were also enhanced. Little effect of germination on its water-binding
capacity was found (P > 0.05); in contrast, oil-holding capacity was improved. Therefore, germination can improve the
functional properties of brown rice starch to some extents.

Key words: germination, brown rice starch, rheological properties, texture properties, thermodynamic properties