Production of phytosterol esters from soybean oil deodorizer distillates

Abstract

Enzymatic esterification and supercritical fluid extraction was used to produce phytosterol esters from soybean oil deodorizer distillates. The raw material was first subjected to a two-step enzymatic reaction; the product obtained mainly comprised fatty acid ethyl esters, tocopherols and phytosterol esters, together with minor amounts of squalene, free fatty acids, free sterols and triacylglycerols. The phytosterol esters were then purified from this mixture using supercritical carbon dioxide. Experimental extractions were carried out in an isothermal countercurrent column (without reflux), with pressures ranging from 200 to 280 bar, temperatures of 45-55 7C and solvent-to-feed ratios from 15 to 35 kg/kg. Using these extraction conditions, the fatty acid esters were completely extracted and, thus, the fractionation of tocopherols and phytosterol esters was studied. At 250 bar, 55 7C and a solvent-to-feed ratio of 35, the phytosterol esters were concentrated in the raffinate up to 82.4 wt-% with satisfactory yield (72%).

Fractionation technologies for liquid mixtures using dense carbon dioxide

“…CIAL-UAM-CSIC research group has developed investigations in two areas of research. Regarding edible oil components and derivatives, it has studied the removal of free fatty acids [28,47], recovery and concentration of minor lipids such as tocopherols, phytosterols, phytosterol esters, carotenoids, and squalene from olive oil and other lipids [1,17,20,22,23,26,53,159]. It has also studied the fractionation of alcoholic beverages [87][88][89], and isolation of antioxidants from orange juice [85,86].…”

“…In the second category, the removal of ethanol and separation of the aromas from alcoholic beverages is the most studied application. In non-aqueous mixtures, there is plenty of information available regarding edible oil components and derivatives (Table 1), specifically on fractionation and concentration of sterols, tocopherols, fatty acids, and carotenoids from pepper oleoresin [49], olive oils [12,17,22,26,28], and other vegetable oils such as those of palm [18,19], sunflower [20], and soybean [7,9,23,[50][51][52][53]. Another important application is the fractionation of fish oil fatty acid alkyl esters [42-47, [54][55][56][57][58] where the main issues that remain to be addressed are the appropriate representation of the phase behaviour for more complex or real mixtures, and the process scale-up [59].…”

Extraction and Enzymatic Modification of Functional Lipids from Soybean Oil Deodorizer Distillate

“…Firstly, SODD was mixed with oleic acid to reduce its melting point and to enhance the free phytosterols esterification. The first enzymatic step (using Candida rugosa lipase) allowed the efficient conversion of more than 90% free phytosterols within 5 h. The second one (using Novozym 435) converted more than 95% FFAs in less than 3 h. The final product obtained was used as starting material to purify FASEs, tocopherols, and FAEEs via supercritical CO 2 extraction (Torres, 2009). Weber and coworkers (Weber et al, 2002) have also reported the use of lipases for the conversion of sterols into steryl esters leading to a higher degree of purity (90%), however the methodology is more complex and involves deacidification, flash chromatography and solvent fractionation.…”

“…Torres and coworkers (Torres, 2007) proposed a two-step enzymatic procedure to obtain FASEs, tocopherols, and fatty acid ethyl esters (FAEEs) from SODD, together with minor amounts of squalene, free fatty acids, free sterols and triacylglycerols. The final product obtained was used as starting material to purify FASEs, tocopherols, and FAEEs via supercritical CO 2 extraction The phytosterol esters were then purified from this mixture using supercritical carbon dioxide (Torres, 2009). Experimental extractions were carried out in an isothermal countercurrent column (without reflux), with pressures ranging from 200 to 280 bar, temperatures of 45-55 °C and solvent-to-feed ratios from 15 to 35 kg/kg.…”

“…These methodologies can work in combination or independently to improve the fractionation of soybean oil deodorizer distillate. Hence, lipase-catalyzed methyl or ethyl esterification of SODD to transform free fatty acids into their corresponding fatty acid methyl or ethyl esters coupled to molecular distillation and/or supercritical fluid extraction has been described as a strategy to improve the separation between tocopherols, sterols and free fatty acids (Torres et al, 2009). Alternatively, enzymatic esterification of the sterols with the fatty acids already present in the deodorizer sludge makes the separation of tocopherols and sterols simpler using short-path distillation or supercritical fluid extraction (Shimada et al, 2000).…”