Effect of chemical refining on the levels of bioactive components and hazardous substances in soybean oil

Effects of deodorization on the content of polycyclic aromatic hydrocarbons (PAHs), 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters (GE) in rapeseed oil using ethanol steam distillation at low temperature

High temperature is beneficial for the removal of polycyclic aromatic hydrocarbons (PAHs) from oil via steam, but leads to an increase in the content of 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters (GE). To inhibit the production of 3-MCPDE and GE during the removal of PAHs, rapeseed oil was deodorized using ethanol steam at low-temperature (140-220 °C) (L-ESD) and the content changes were studied for PAHs, 3-MCPDE and GE, and compared with conventional high-temperature water steam deodorization (H-WSD) (250 °C for 60 min). The removal rates of PAHs in L-ESD oil can be higher than those in conventional H-WSD oil, and the contents of 3-MCPDE and GE in L-ESD oil (140-180 °C for 60-100 min) ranged from 48.32 to 73.65 % and 50.49-69.90 %, respectively, in H-WSD oil due to the lower temperature of ethanol steam deodorization. These results indicate that L-ESD is beneficial in minimizing the contents of PAHs, 3-MCPDE and GE in vegetable oil.

Effect of Chemical Refining on the Reduction of β-Carboline Content in Sesame Seed Oil

β-carbolines (harman and norharman) are potentially mutagenic and have been reported in some vegetable oils. Sesame seed oil is obtained from roasted sesame seeds. During sesame oil processing, roasting is the key procedure to aroma enhancement, in which β-carbolines are produced. Pressed sesame seed oils cover most market share, while leaching solvents are used to extract oils from the pressed sesame cake to improve the utilization of the raw materials. β-carbolines are nonpolar heterocyclic aromatic amines with good solubility in leaching solvents (n-hexane); therefore, the β-carbolines in sesame cake migrated to the leaching sesame seed oil. The refining procedures are indispensable for leaching sesame seed oil, in which some small molecules can be reduced. Thus, the critical aim is to evaluate the changes in β-carboline content during the refining of leaching sesame seed oil and the key process steps for the removal of β-carbolines. In this work, the levels of β-carbolines (harman and norharman) in sesame seed oil during chemical refining processes (degumming, deacidification, bleaching and deodorization) have been determined using solid phase extraction and high performance liquid chromatography-mass spectrometry (LC-MS). The results indicated that in the entire refining process, the levels of total β-carbolines greatly decreased, and the adsorption decolorization was the most effective process in reducing β-carbolines, which might be related to the adsorbent used in the decolorization process. In addition, the effects of adsorbent type, adsorbent dosage and blended adsorbent on β-carbolines in sesame seed oil during the decolorization process were investigated. It was concluded that oil refining can not only improve the quality of sesame seed oil, but also reduce most of the harmful β-carbolines.

Effects of Deodorization on the Formation of Processing Contaminants and Chemical Quality of Sunflower Oil

Tocopherols and phytosterols are generally considered to be nutritionally beneficial, and 3-Monochloropropane-1,2-diol esters (3-MCPD esters), glycidyl esters (GEs) and trans fatty acids (TFAs) are generally considered to be harmful. The high temperature deodorization step is when these harmful 3-MCPD esters, GEs and TFAs are generated. Knowing how deodorization conditions affect levels of these substances is essential for designing refining processes that will produce nutritious, high quality edible oils. This study analyzed the changes of these components of sunflower oil at different temperatures (210, 230, 250 and 270°C) and times (60, 80, 100 and 120 min) during deodorization. Our research found that during the whole deodorization process (including undeodorized sunflower oil), the contents of 3-MCPD esters, GEs and TFAs all progressively increased, from 0.47 to 11.18 mg/kg, 0.24 to 18.42 mg/kg and 0.062% to 0.698%, respectively. However, the deodorization process significantly decreased the levels of tocopherols (from 535.94 to 240.26 mg/kg) and phytosterols (from 2803.58 to 1864.34 mg/kg). Meanwhile, the retention ratios of total tocopherols and total phytosterols also decreased from 96.29% to 44.83% and 92.29% to 66.50%, respectively.

Oxidative Quality of Acid Oils and Fatty Acid Distillates Used in Animal Feeding

Simple Summary

Feed producers and farmers seek alternative and economical fat ingredients to supply animals with energy and beneficial components, such as natural antioxidants. Some byproducts from the edible oil refining industry, such as acid oils (AO) and fatty acid distillates (FAD), fulfil these requirements, but differences in the animal performance have been reported as their main drawback, which might be due to their high variable composition, including their oxidation status. Therefore, the valorization of these byproducts as feed ingredients requires ensuring standardized products with adequate quality in terms of oxidation parameters. In this study, 92 AO and FAD were characterized, finding a huge variability in their oxidation status and stability. They all showed low primary oxidation values (peroxide values). The content of secondary oxidation compounds was higher in FAD (which are released from physical refining processes) than in AO (which originate from chemical refining), while polymeric compounds were higher in the latter. The fatty acid and tocol compositions that were related with the botanical origin influenced their oxidative stability. Thus, in the quality control of these products, apart from the compositional parameters, it is recommended to include the evaluation of the oxidation status, both by primary and secondary oxidation parameters.

Abstract

Acid oils (AO) and fatty acid distillates (FAD) are byproducts from chemical and physical refining of edible oils and fats, respectively. Their high energy value makes their upcycling interesting as alternatives to conventional fats in animal feeding. The objective of this study is to characterize their oxidative quality and to provide recommendations about their evaluation for animal feeding purposes. The oxidation status (peroxide value (PV), p-Anisidine value (p-AnV), % polymeric compounds (POL)), the oxidative stability (induction time by the Rancimat at 120 °C (IT)), the fatty acid composition (FA), and tocopherol and tocotrienol content of 92 AO and FAD samples from the Spanish market were analyzed. Both AO and FAD showed low PV (0.8 and 1 meq O₂/kg); however, p-AnV was higher in FAD (36.4 vs. 16.4 in AO) and POL was higher in AO (2.5% vs. not detected in FAD) as a consequence of the type of refining process. The botanical origin of AO and FAD influenced FA and tocol composition, and they influenced IT. A high variability was observed for most analyzed parameters, reinforcing the need for standardizing AO and FAD to obtain reliable feed ingredients and to include primary and secondary oxidative parameters within their quality control.

Changes of physicochemical properties, oxidative stability and cellular anti-inflammatory potentials for sea-buckthorn pulp oils during refining

The impact of the refining process on physicochemical properties, oxidative stability and cellular anti-inflammatory potentials of sea-buckthorn pulp oil (SBO) was investigated in this study. The results showed that acid and peroxide values of the tested SBOs decreased significantly after the refining process, while oxidative stability index (OSI) and anti-inflammatory potentials, measured as reduction in cellular inflammatory cytokine production, increased significantly. Interestingly, bleaching caused an unexpected increase in tocopherols as well as the greatest reduction in polycyclic aromatic hydrocarbons (PAHs). According to correlation analyses, tocopherol concentrations were significantly and positively correlated with OSI values and cellular anti-inflammatory potentials, while PHAs were negatively correlated with these factors. In general, refining is an effective way to improve the oxidative stability and anti-inflammatory capacity of SBO.

The impact of the refining process on physicochemical properties, oxidative stability and cellular anti-inflammatory potentials of sea-buckthorn pulp oil (SBO) was investigated in this study.