Effects of processing on quality of soybean oil

Abstract

The fate of major and minor components of soybean oil is examined at each stage of processing. Relationships are then drawn upon the effect on the quality of finished oil. General topics covered are (a) triglycerides and polyunsaturated fatty acids, (b) free fatty acids, (c) mono‐ and diglycerides, (d) phospholipids, (e) minor constituents, such as tocopherols, color bodies, and metal ions, (f) rearrangement and decomposition products, (g) foreign or toxic compounds not native to soya and (h) other additives, such as refining aids.

Refining of Roundup Ready® soya bean oil: Effect on the fatty acid, phytosterol and tocopherol profiles

“…The high decrease of tocopherols observed after neutralisation is in good agreement with other reports concerning the chemical refining of other vegetable oils [2]. Jung et al [5] and Sleeter [6] reported lower decreases (7.4 and 11.9%, respectively) after soya bean oil neutralisation, possibly because of the use of lower concentrations of NaOH solution than that in the industrial process under study. This decrease can be attributed to tocopherols instability caused by the contact of oil with air and concentrated alkali solution during this refining step [23].…”

“…This reduction was lower than other values (32, 36 and 41%), reported by Jung et al [5], Sleeter [6] and Medina-Juárez et al [22], respectively, concerning the refined soya bean oil. Tocopherols are degraded by high temperatures, high pH and certain metals such as iron and copper [23], thus, under the refining process conditions they can be easily lost.…”

“…After neutralisation, the oil was washed to remove the remaining soaps, contributing to a slight further reduction of phytosterols. Both the neutralisation and washing steps were responsible for a 14.9% of total sterols reduction, which is a lower decrease than the reported by Sleeter [6] and Verleyen et al [19] for soya bean oil refining (21.2 and 19.6%, respectively). Verleyen et al [19] studied the effect of parameters such as the concentration and volume of NaOH solution on soya bean crude oil submitted to a chemical refining process at laboratory scale, concluding that the use of high NaOH concentrations (15%) induces low losses on phytosterols during the chemical neutralisation, while the use of low strength solutions (2.5-7.5%) were responsible for higher losses.…”

“…However, they have been performed several years ago [4][5][6], before the first commercialisation of genetically modified organisms (GMO). As nowadays GMO have been a topic of discussion among the scientific community and consumers, and since GM crops are widely used to obtain edible oils, the oilseeds from RR soya bean were the subject of the present study.…”

Microemulsion as Sample Preparation for Direct Flame Atomic Absorption Spectrometry (FAAS) Determination of Total Iron in Crude and Refined Vegetable Oils

“…The fact that all Fe concentrations in the analyzed refined vegetable oils were lower than the LOQ can be explained by considering that the oil refining process was effective for removing Fe, [51][52][53] 53 and 0.5-1.5 mg kg -1 of Fe in crude canola oil 52 have been previously reported.…”