Varied reduction of ochratoxin A in brown and white rice during roasting

Ochratoxin A (OTA) is a possible human carcinogen commonly found in various agricultural commodities worldwide. While this potent nephrotoxin tends to survive common food processes and contaminate food products, certain process with higher temperature treatments may reduce OTA contents. Roasting has been suggested as a possible method to reduce OTA in coffee beans with up to 90% reduction, which may be applied to other food commodities. In this study, the possible influence of fibres on the reduction of OTA was investigated with brown and white rice with 2.2 and 6.7% of total dietary fibre content, respectively, roasting at two different temperatures (160 and 200 °C) for up to 30 min. The results showed that the rate and extent of OTA reduction were dependent on time, temperature, and rice type; greater than 60% of OTA reduction were achieved at 200 °C for 30 min for white rice and 37% for brown rice at the same conditions. No significant differences in reduction were observed between the samples roasted at 160 °C for 30 min and 200 °C for 15 min for both the white and brown rice, while white rice roasted at 160 °C for 15 min during roasting may be affected by the presence of fibre and/or fat in the cereal grains.