Isolation of tocopherol and sterol concentrate from sunflower oil deodorizer distillate

Abstract: The lipase from Rhizomucor miehei (RML), formerly Mucor miehei, is a commercially available enzyme in both soluble and immobilized forms with very high activity and good stability under diverse experimental conditions (anhydrous organic solvents, supercritical fluids, etc.). The uses of the enzyme were initially oriented towards food industry, that way the enzyme has found a broad application in this area. This review intends to show the enzyme features and some of the most relevant aspects of the use of this interesting enzyme in oils and fats modification. The enzyme has been the first lipase whose structure was reported and its interfacial activation is very well known, making this enzyme a good template for modeling studies. Finally, the main uses of the enzyme in fatty acids, oils and fats modification will be revised (hydrolysis of glycerides, transesterification, esterification, acidolysis and interesterification). This lipase seems to be advantageous when compared to other lipases mainly in esterificaton reactions in anhydrous media, while other lipases can be preferred in transesterification reactions.

Abstract: Egyptian mango seeds were collected as wastes from local fruit processing units and the kernels were separated and dried. This study was carried out on mango seed kernels to clarify their proximate composition, amino acids, phenolic compounds and the characteristics of the extracted oil including unsaponifiable matter constituents, lipid classes and fatty acid composition. Mango seed kernels contained a considerable amount of total phenolic compounds, total lipid, unsaponifiable matter, and a low amount of crude protein, but the quality of protein was good because it was rich in all essential amino acids. Eight phenolic compounds were identified; tannin and vanillin were in highest amounts. Unsaponifiable matter showed the occurrence of high amounts of squaline followed by sterols and tocopherols. Stearic acid was the main saturated fatty acid, while oleic acid was the major unsaturated fatty acid in all lipid classes. The fatty acid composition of total lipid and neutral lipid was similar, while phospholipid had a high amount of palmitic, linoleic and linolenic acids.

Abstract: Differential scanning calorimetry (DSC) is used to study the melting process of three pure fatty acids (palmitic, stearic and oleic) and both their binary and ternary mixtures. The results obtained for palmitic (T=337 K, ΔH=208.2 J g−1) and stearic (T=344 K, ΔH=210.8 J g−1) acids indicate the existence of a simple process. However, oleic acid presents a reversible solid–solid phase transition (T=225 K, ΔH=3.6 J g−1) prior to melting (T=278 K, ΔH=75.5 J g−1). The solidification of this acid is a complex process, since a liquid–liquid transformation (T=272 K, ΔH=−10.5 J g−1) takes place prior to the change of the liquid–solid aggregation state (T=260 K, ΔH=−61.0 J g−1). The presence of the oleic acid in the binary and ternary mixtures produces melting points at different levels of temperature. The eutectic temperature is determined for the palmitic/stearic mixture (T=331 K), its non-ideal behavior being demonstrated. The melting heat in the binary mixtures hardly changes, while in the ternary mixtures a lineal decrease is observed when the oleic composition is increased.

Abstract: Because of its complex nature, the analysis of deodorizer distillate is a challenging problem. Deodorizer distillate obtained from the deodorization process of vegetable oils consists of many components including free fatty acids, tocopherols, sterols, squalene and neutral oil. A gas chromatographic method for the analysis of deodorizer distillate without saponification of the sample is described. After a concise sample preparation including derivatization and silylation, distillate samples were injected on column at 60°C followed by a gradual increase of the oven temperature towards 340°C. The temperature profile of the oven was optimized in order to obtain a baseline separation of the different distillate components including free fatty acids, tocopherols, sterols, squalene and neutral oil. Good recoveries for δ-tocopherol, α-tocopherol, stigmasterol and cholesteryl palmitate of 97, 94.4, 95.6 and 92%, respectively were obtained. Repeatability of the described gas chromatographic method was evaluated by analyzing five replicates of a soybean distillate. Tocopherols and sterols had low relative standard deviations ranging between 1.67 and 2.25%. Squalene, mono- and diacylglycerides had higher relative standard deviations ranging between 3.33 and 4.12%. Several industrial deodorizer distillates obtained from chemical and physical refining of corn, canola, sunflower and soybean have been analyzed for their composition.

Abstract: Isolation of minor lipid components from complex lipid mixtures is receiving increased attention due to their biological activity and health benefits. Therefore, properties, health benefits and processing aspects of minor bioactive lipid components were reviewed. Literature solubility data of binary mixtures of minor lipid components (β-carotene, α-tocopherol, stigmasterol and squalene) and supercritical carbon dioxide (SCCO2) were correlated using Chrastil’s equation to determine the general trends of solubility behavior as affected by operating conditions and solute properties. Model parameters were estimated for the whole temperature range (a, b, k) and at each temperature (b′, k′). The slopes of solubility isotherms (k′) were in the range of 4.9–10.6 for β-carotene, 4.5–9.6 for α-tocopherol, 4.9–8.0 for stigmasterol and 7.3–7.6 for squalene. Estimated model parameters were used to compare solubility behavior of these solutes with components of olein glyceride series (oleic acid and triolein) as representatives of major lipid classes found in fats and oils. The findings provide the basis for the study of multicomponent lipid mixtures. Differences in the solubility behavior of components and the effect of operating conditions on solubility can be exploited for fractionation of these multicomponent mixtures to isolate the bioactive minor lipid components.

Abstract: Separation of sterols and tocopherols from fatty acids in deodorizer distillate was facilitated through lipase-catalyzed modification of fatty acids in canola, mixed and soya deodorizer distillates. The fatty acid esterification with methanol catalyzed by SP-382 (an immobilized nonspecific lipase) proceeded rapidly, with conversion of fatty acid to methyl ester in 5 h being 96.5, 83.5 and 89.4%, respectively. A model mixture of pure oleic acid and dl-α-tocopherol was used to study any potential side reactions that may lower the tocopherol content during the esterification reaction. Under the conditions employed, the loss of tocopherol was less than 5%. Simple vacuum distillation (1–2 mm Hg) was employed to remove the volatile fraction (methyl esters of fatty acids, some fatty acids and other volatiles) of the esterified deodorizer distillate, leaving behind sterols, sterol esters and tocopherols. Sterols and tocopherols were almost completely retained in the residue fraction with recoveries in the range of 95%. Overall recoveries of sterols and tocopherols after esterification and distillation were over 90% for all the deodorizer distillate samples.

Abstract: Supercritical fluid extraction (SFE) has been widely applied as a promising alternative to current extraction processes used in the food and pharmaceutical industries. SFE has some advantages over conventional separation processes such as liquid-liquid extraction, distillation, and adsorption. The most important advantage of utilizing SFE is the easy separation of the solvent from the extracted material without solvent residue. Further, supercritical fluids provide lower mass transfer resistance than those in conventional separation processes. A number of references dealing with the basic principles and applications of SFE are now available [1-3]. The objective of this study is therefore to examine the feasibility and technical merits of SFE as a potential alternative to molecular distillation for enriching tocopherols effectively from soybean sludge. In this regard, the solubilities of both sterol-removed soybean sludge and esterified soybean sludge in SC-CO2 were determined by a flow-through SFE system at temperature and pressure ranges f 35–70∘C and 200–400 bar, respectively. The tocopherol content in the extracts collected continously at equilibrium conditions up to the approximate 70 wt% extraction rate of the feed was checked by HPLC at each interval. The results of these initial feasibility experiments could provide fundamental information for the suitable application of a continous-type SFE for concentrating tocopherols.

Abstract: Polyphenols were extracted from the rape of Israeli olive oil using hexane, acetone and ethanol in a simple sequential procedure yielding three fractions (A,B,C). Fraction A (extracted with hexane) contained few polyphenols (0.05%), while Fraction B (extracted with acetone) and Fraction C (extracted with ethanol) contained about 5% polyphenols each. Fractions B and C were also found to contain the highest ortho-di-phenol concentration (about 3%). The addition of purified Fraction B at a level of 100 ppm to refined olive or soybean oils partially inhibited the oxidative deterioration when the oils were stored in the dark at 100 C.