Abstract
A crude soybean oil, several of its refinery by-products (described as soapstock, deodorizer distillate, and clabber stock), and the completely refined oil were analyzed for pesticide residues. Fourteen organochlorine pesticides and pesticide metabolites were found in the deodorizer distillate; 5 of these were also found in the clabber stock. Levels in these byproducts ranged from 0.3 to 8 ppm. Only endrin and dieldrin were detected in the crude oil at levels of 0.01 and 0.05 ppm, respectively. Forty to 150 times these levels were found in the deodorizer distillate and clabber stock. Pesticide residues were not detected in the refined oil or in the soapstock at limits of detection for dieldrin of about 0.01 and 0.1 ppm, respectively. The method used by the Food and Drug Administration to analyze fats and oils for multiple organohalogen pesticide residues was inadequate for the extraction of pesticide residues from vegetable oil refinery by-products. The method used to analyze the crude vegetable oil and the refinery by-products involved dissolution of the oil samples in ethyl acetate- toluene, filtration if necessary, cleanup by gel permeation chromatography, and then Florisil column chromatography. The oil was isolated from aqueous-oil mixtures by extraction with hexane before analysis. The crude soybean oil was fortified with 12 organohalogen pesticides and Aroclor 1254 at levels of 0.5-3.7 ppm. Recoveries ranged from 83 to 102%.
By-Products of the Refining of Soybean Oil as Pigment Sources for Poultry