After peanut oil cold processing, residues of four pesticides were 2.05-3.63 times higher in the peanut oil than in the peanut meal itself. Pesticides concentrating in the oil include chlorpyrifos, deltamethrin, methoxyfenozide and propargite. This is of concern as peanut oil is commonly used in frying, such as in the making of french fries or chips in a commercial setting. Researchers also found pesticides from the oil were migrating into the food being cooked. During the frying of "chips" - up to 11.06% of pesticides in the oil was transferred to the fried food.
ABSTRACT
Background: Pesticide contamination in oil crops and processed products is an important food safety concern. The study was aimed to investigate the pesticide residue changes in press processing of peanut oil and frying of chips.
Results: Five pesticides - chlorpyrifos, deltamethrin, methoxyfenozide, azoxystrobin and propargite - which are often applied during growth period in peanut plants, were selected to investigate their residue changes in cold press processing of peanut oil and frying of potato chips. Results showed that the residues of the five pesticides were decreased by 3.1-42.6% during air-drying before oil pressing. The residues of chlorpyrifos, deltamethrin, methoxyfenozide and propargite in peanut oil were 2.05-3.63 times higher than that in peanut meal after cold pressing of the oil, except for azoxystrobin having a slightly lower residue in peanut oil, with 0.92 times that in peanut meal. The processing factors of the five pesticides in peanut oil ranged from 1.17 to 2.73 and were highly related to the log Kow of the pesticides. The higher the log Kow , the more easily was the pesticide partitioned in the peanut oil. Besides, as frying time increase during preparation of chips, the concentration of pesticides in peanut oil decreased gradually by 6.7-22.1% compared to the first frying. In addition, 0.47-11.06% of the pesticides were transferred to the chips through frying with contaminated oil.