Distributions of Polycyclic Aromatic Hydrocarbons and Phthalic Acid Esters in Gums and Soapstocks Obtained from Soybean Oil Refinery

Abstract

Soybean oil gums and soapstocks are important by-products that may potentially be contaminated by persistent organic pollutants (POP) such as polycyclic aromatic hydrocarbons (PAH) and phthalic acid esters (PAE), thus lowering the value when using them as starting materials to produce animal feed additives, food industry ingredients, and pharmaceutical products. In the present work, PAH and PAE distributions in these two types of by-products were detected using solvent extraction-solid phase extraction purification coupled with gas chromatography-mass spectrometry. Total PAH and PAE amounts in the soapstocks were significantly higher than those in the gums, thus indicating that neutralization showed much higher removal efficiency than degumming in terms of PAH and PAE eliminations. Meanwhile, the results proved that the concentrations of these two kinds of contaminants in the soybean oil gums and soapstocks were much higher than those in the soybean oils, suggesting that further investigations were needed and that the contents of PAH and PAE in soybean oil refining by-products should be carefully monitored and regulated.

Review on Occurrence, Sources of Contamination, and Mitigation Strategies of Phthalates in Vegetable Oils

“…This phenomenon is widespread in the production of edible oils, especially vegetable oils derived from plant seeds, such as camellia seed oil, perilla seed oil, evening primrose oil, soybean oil, sesame oil, peanut oil, and the like. [ 36 ]…”

“…More and more studies [34][35][36][37] have shown that PAEs widely exist in the production, processing, storage, and transportation of vegetable oils. During the production process of edible vegetable oil, PAEs pollution may occur to varying degrees during the raw material collection, production and processing, and storage and transportation stages.…”

“…This phenomenon is widespread in the production of edible oils, especially vegetable oils derived from plant seeds, such as camellia seed oil, perilla seed oil, evening primrose oil, soybean oil, sesame oil, peanut oil, and the like. [36] Shi [46] and others' research shows that mulching covers significantly increase the concentration of PAEs in wheat grains. The concentration of PAE in the grain covered by the mulching film ranged from 4.1 to 12.6 mg kg −1 , which was significantly higher than that in the mulch-free land.…”