Natural antioxidants from agro-wastes enhanced the oxidative stability of soybean oil during deep-frying
Eman M. Abdo, Omayma E. Shaltout, Hanem M. M. Mansour
Abstract
Plant leaves are an abundant natural antioxidant source that could effectively alternate synthetic antioxidants. Here, we investigated the effect of the lyophilized pomegranate/orange/beetroot leaves extract (POB) (1:1:1), as a natural antioxidant , in retarding the thermo-oxidative degradation of the soybean oil during the deep-frying. To achieve this, we examined the effect of the POB extract at 200, 400, and 800 μg/ml and the potentiated effect of POB-400 μg/ml on butylated hydroxytoluene (BHT) at 100 μg/ml versus that of BHT-200 μg/ml. The extract at 200 and 400 μg/ml weakly retarded the oxidation. Whereas POB-800 μg/ml and POB/BHT (400/100 μg/ml) inhibited the oil oxidation at the early stages, the peroxide value was <10 meq O 2 /kg. POB-800 μg/ml and POB/BHT reduced the total oxidation (TOTOX) by 55% and 64%, respectively, compared to the raw oil, and decreased the formation of the malondialdehyde by nearly 80%. Besides, the gas chromatography results proved that the POB extract efficiently retarded the oxidation process during discontinuous frying. Consequently, the POB extract could be a promising alternative to BHT in inhibiting the thermo-oxidative degradation of the soybean oil during the frying up to 50 frying batches.