The inherent DPPH activity of fresh beetroot juice was equal to
0.28 1.30 mg AAE/g dried sample. After the vacuum drying impregnation with the beetroot juice, the DPPH scavenging activity in all the rice samples was significantly increased (p < 0.05, Table 2). This increment was possibly associated with the increased cracking degree. The DPPH activity was linearly increased with the
beetroot juice content for all the rice samples (R2 ¼ 0.89e0.99). The
rice grains with different storage periods revealed significantly different antioxidant absorption capabilities (p < 0.05) while the impact of rice varieties were insignificant (p > 0.05). The highest DPPH activity gain after juice impregnation was determined for SPT which was stored for one year. That of the other samples was similar. The DPPH activity gain of KML stored for one month tren- ded to be the lowest. It seems that the DPPH activity changes in the rice samples are complex. It is potentially not only associated with the rice physical changes (e.g., crack formation) but chemical changes (e.g., interactions between antioxidants in beetroot juice and rice).