Effect of environment on rice phenolic content and antioxidant activity

The effect of cultivation environment on phenolic content and respective antioxidant activity was examined in whole grain rice. Rice samples examined included pigmented and non-pigmented varieties from New South Wales (NSW) and Queensland. It was observed that cultivation environment had a substantial impact on rice phenolic content and antioxidant activity. Anthocyanin and proanthocyanidin, the two major bioactive compounds present in pigmented rice (Purple and Yunlu29) also exhibited considerable variation between the two locations. While environment affected various phenolic compounds across the varieties, variation in antioxidant activity was mainly observed in compounds that had high antioxidant activity. Hence, difference of antioxidant activity was more prominent in pigmented Yunlu 29 and Purple compared to Reiziq, the brown rice variety. The study also observed that not every phenolic compound present was affected by environment, some were stable, while others were more susceptible. Some of these susceptible compounds were predominant contributors of antioxidant potential in rice. Therefore, further studies and optimisation of cultivation environment can aid in production of higher quality grains in relation to their end use as functional foods and food ingredients.