The present study determined the effect of storage temperature
and storage time on the radical scavenging activity and bioavailable
compounds of black and red-colored rice varieties in
Thailand. The results show that storage time had a strong
influence on radical scavenging activity and the total
anthocyanins, polyphenol and β-carotene contents of colored
rice cultivars, whereas storage temperatures had weak effects on
radical scavenging activity and the bioactive compounds. The
increasing β-carotene content of the rice during storage indicates
the contribution of non-phenolic antioxidants on the increased
radical scavenging activity in black rice. These data demonstrate
the importance of storage time and temperature on the radical
scavenging activity and bioactive compounds of pigmented rice
cultivars. This research provides valuable information that can be
used in the preparation of guidelines for designing the appropriate
packages of pigmented rice cultivars while maintaining their
antioxidant activities and components. In addition, this research
has also indicated the role of non-phenolic antioxidants on the
radical scavenging activity of colored rice and that the loss of
polyphenols in rice during storage might be compensated for by
the appearance of other non-phenolic antioxidants. Further
research is needed to examine the effects of aging and storage
temperature on non-phenolic antioxidant compounds, such as
vitamin E, carotenoids, minerals and trace elements.