Abstract: Changes in antioxidant properties and degradation of bioactives in palm oil (PO) and rice bran oil (RBO) during deep-frying were investigated. The alpha (α)-tocopherol, gamma (γ)-tocotrienol and γ-oryzanol contents of the deep-fried oils were monitored using high performance liquid chromatography, and antioxidant activity was determined using 2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity. Results revealed that the antioxidant activity of PO decreased significantly (p < 0.05), while that of RBO was preserved after deep-frying of fries. As expected, the concentration of α-tocopherol in PO and γ-tocotrienol in both PO and RBO decreased significantly (p < 0.05) with increased frying. Results also showed that γ-tocotrienol was found to be more susceptible to degradation compared to that of α-tocopherol in both PO and RBO. Interestingly, no significant degradation of α-tocopherol was observed in RBO. It is suggested that the presence of γ-oryzanol and γ-tocotrienol in RBO may have a protective effect on α-tocopherol during deep-frying.
Keywords: vegetable oils; deep-frying; kinetic degradation; free radical scavenging; oil antioxidants
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Hamid, A.A.; Dek, M.S.P.; Tan, C.P.; Zainudin, M.A.M.; Fang, E.K.W. Changes of Major Antioxidant Compounds and Radical Scavenging Activity of Palm Oil and Rice Bran Oil during Deep-Frying. Antioxidants 2014, 3, 502-515.
Hamid AA, Dek MSP, Tan CP, Zainudin MAM, Fang EKW. Changes of Major Antioxidant Compounds and Radical Scavenging Activity of Palm Oil and Rice Bran Oil during Deep-Frying. Antioxidants. 2014; 3(3):502-515.
Hamid, Azizah A.; Dek, Mohd S.P.; Tan, Chin P.; Zainudin, Mohd A.M.; Fang, Evelyn K.W. 2014. "Changes of Major Antioxidant Compounds and Radical Scavenging Activity of Palm Oil and Rice Bran Oil during Deep-Frying." Antioxidants 3, no. 3: 502-515.