Antioxidant Effects of Green Tea Leaf Extract on Chemical properties of Corn Refined Oil of Microwave Fried Potatoes

Oxygen, light, heat, metal ions, and enzymes are among the agents that oxidize oils, fats, and high-fat food products which result in oxidative spoilage. Due to the toxicity and cancer risk of oxidative agents, the use of synthetic antioxidants is important for delaying the oxidation processes. The purpose of this study was to evaluate the protective effect of natural antioxidants including green tea leaf extract and butylated hydroxytoluene (BHT) on the oxidation of the corn refined oil of microwave-heated fried potatoes.

To this end, corn refined oil and corn oil were treated with green tea leaf extracts (i.e., 200, 400, 600, and 800 ppm), followed by treating the oils with a combination of green tea leaf extract (600 ppm) and BHT (200 ppm). The samples with no anti-oxidant treatments were used as the controls. Eventually, several parameters related to the corn oils were determined, including peroxide content, acidity, polar compounds, and ionic bond conjugates.

Based on the results, significant increases were observed in peroxide, acidity, polar compounds, and ionic bond conjugates in the corn refined oil of microwave fried potatoes (P < 0.05). On the other hand, the results showed that the heating process reduced peroxide content (P < 0.05). However, acidity increased significantly during the heating process (P > 0.05) and the lowest acid value was observed in the mixture of 600 ppm of the green tea leaf with 200 ppm of the BHT. There was no significant difference between the control group and the samples treated with 200 ppm of the green leaf extract (P < 0.05) in terms of polar components. In addition, a significant decrease was found in the conjugated dienes by increasing the green tea leaf extract concentration (P < 0.05). Finally, the highest protection was achieved in the oils that were treated with a combination of green tea leaf extract and BHT.

In general, the green tea leaf extract and BHT have antioxidant activities that make them suitable agents for use in food protection industries.