Analysis of the physiochemical properties of rice induced by postharvest yellowing during storage.

Pasting properties indicated that the yellowing process led to a reduced peak viscosity and breakdown value of the postharvest yellowing (PHY) rice compared to corresponding normal one. More importantly, the current study revealed that both moduli of G' and G″ of the gel formed from the PHY rice was lower than that of its corresponding rice and the yellowing significantly reduced the area of the hysteresis curve. Thus, it is proposed that PHY may inhibit the formation of a continuous network structure. Studies of moisture absorption dynamics and low-field NMR suggested that the yellowing process led to a faster moisture absorption and de-absorption, indicating a faster moisture fluidity in rice kernels induced by yellowing process. Potent of the "capillary channels" might be formed during rice yellowing, and these structural characteristics may be associated with its higher digestibility due to the accelerated diffusion of the digestive enzymes in rice kernels.