Abstract: The gelatinization properties, rheological properties, Fourier transform infrared spectroscopy (FTIR) spectra and microstructure of glutinous (G) and japonica (J) rice blends at different ratios were studied. The gelation behavior was explored by analyzing storage modulus (G’), gelation velocity (?g) and gelation acceleration (αg) of the blend gels. The relationship of rice cake quality changes with the characteristics of the blend system was analyzed. The results indicated that the blend system was a weak gel system. The stability of hot paste and the gelling ability of cold paste considerably changed with the increase of glutinous rice, and the viscosity, breakdown and setback value decreased significantly (P < 0.05); the dynamic rheological properties G’ and ?g declined under both non-isothermal and isothermal conditions, whilst the opposite was true for the phase tangent (tan δ), activation energy (Ea) and αg. Meanwhile, in the frequency sweep, the tan δ curves of the blend systems with G/J ratio of 1:2.5–1:2.0 gradually became smooth in the low frequency range, while for the low-glutinous rice systems (G/J ratio = 1:3.0–1:5.0), the changes in gel properties reached a critical value at G/J ratio of 1:3.0, leading to the formation of a better network structure with higher water absorption rate and better gel stability. With increased proportion of glutinous rice, the consistency coefficient (K) from the Power-Law model and the thixotropic loop area decreased, and the flow characteristic index (n) increased, indicating good shear stability and thixotropy. As a result, in the gelatinization degree of rice cake decreased continuously, reaching a critical value of 90.48% at G/J ratio of 1:3.0. As indicated by the changes in peak area ratio at 997 cm-1/1 155 cm-1, 1 020 cm-1/1 155 cm-1, and 1 654 cm-1/1 155 cm-1 in the FTIR spectra, increased proportion of glutinous rice could enhance the water-binding capacity of the blend system, and the bound water molecules led to changes in the gelation behavior by interacting with the single helix structure of amylose and expanding the amorphous region. Therefore, the G/J ratio of 1:3.0 blend system formed a dense gel network structure without needle-like morphology and with uniform pore size distribution, and the resulting rice cake had the highest water absorption rate and elasticity.

Key words: glutinous/japonica rice blends, rheological property, gelation behavior, kinetics, Fourier transform infrared spectroscopy, rice cake