Effect of refinement and production technology on the molecular composition of edible cottonseed oils from a large industrial scale production

Unrefined, refined and refined-deodorized cottonseed oils from pressing or extraction technologies were screened using NMR and GC-MS. GC-MS of intact and derivatized oils allowed tentative annotation of ~100 compounds. These included fatty acids (FA), linoleic (51-57%), oleic (18-23%), palmitic (21-23%) and stearic acids (2-2.2%) in hydrolysed oils, and β-sitosterol (31-43%), free FA (7-34%), γ- and α-tocopherol (11-22%), and squalene (2-4%) in intact oils. NMR spectra of intact oils contained 90 resonances and were dominated by methylene (41%), methyl (14%), and methine (6.8%) protons of FA and triglycerides. Analysis of the molecular profiles revealed a dominating effect of the processing followed by the production technology. Oil refinement reduced undesirable free FA, diglycerides and gossypol, but increased hydrocarbons and aldehydes. The refined press oil contained higher levels of steroids and less free FA compared to refined extract oil. Thus, the study showed potentials of foodomics to evaluate the quality of edible oils.