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Title:A. Chlorinated Pesticides in Soybeans, Soybean Oil, and Its by-Products During Processing. B. Effect of Thermal Oxidation on Mixtures of Palm and Soybean Oil
Author(s):Chaudry, Muhammad Munir
Department / Program:Food Science
Discipline:Food Science
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Agriculture, Food Science and Technology
Abstract:A. Soybean samples were collected from seven different locales in Central Illinois and subjected to analysis for chlorinated pesticides. Different parts of the beans showed varying levels of residue concentrations. It was found that pesticide residues had a tendency to accumulate, in descending order, in hypocotyls, hulls, and cotyledons, on the basis of ground samples. When the oils extracted from the same fractions were analyzed, much higher concentrations of residues were located in hulls than hypocotyls, which had greater concentrations than cotyledons. Crude, refined, bleached, and deodorized oils, soapstock, Fuller's earth sludge, and deodorization condensate were analyzed for BHC isomers, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, DDT, DDD, and DDE. None of the processing steps except deodorization were completely effective in the removal of chlorinated pesticide residues. Oil deodorized at 250(DEGREES)C under 1-5 mm pressure, was almost free of such residues, whereas all the residues were concentrated in the deodorization condensate. It is recommended that the hulls, and the oil processing by-products used in the animal feeds should be thoroughly monitored for pesticides, and the waste materials should be disposed of properly, so as not to contaminate the environment.
B. The effects of interesterification of the vegetable shortenings, and of the incarporation of palm oil into partially hydrogenated soybean oil, on the changes in physical and chemical constants during deep fat frying, were studied. Under commercial deep fat frying conditions, there was an increase in free fatty acids, saponification value, index of refraction and carbonyl value, and a decrease in iodine value of all the shortenings studied. Most of the determinations seemed to be independent of the interesterification and showed only small differences due to initial degree of unsaturation of the oils. Although noneluted oxidized and polymeric components, analyzed by GLC internal standardization method, increased upon heat treatment of the oils, the changes were greater in highly unsaturated oils.
High pressure gel permeation chromatography was employed to analyze monomeric, dimeric and trimeric triglycerides from thermally oxidized soybean oil. Soybean oil heated for 40 hours, under commercial deep fat frying conditions, contained 1.32% trimeric and 7.91% dimeric triglycerides. The fractions of heated soybean oil collected from reverse phase HPLC were analyzed by GLC using internal standards. The GLC analysis of fatty acyl methyl esters revealed that the first fractions contained mostly short chain and highly unsaturated fatty acids as triglycerides, which correspond to the assigned equivalent carbon numbers. The last fractions contained triglycerides mostly with long chain and more saturated fatty acids. Dimer acid content of the reverse phase HPLC fractions from heated soybean oil ranged from 0.01% to 1.17%. The scope of reverse phase high pressure liquid chromatographic, high pressure gel permeation chromatographic, gas liquid chromatographic, and thin-layer chromatographic techniques for the analysis of thermally oxidized lipids has been discussed.
Issue Date:1980
Description:120 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.
Other Identifier(s):(UMI)AAI8026461
Date Available in IDEALS:2014-12-13
Date Deposited:1980

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