Soybean oil deodorization

Chem. Descrip. Refined, bleached, deodorized soybean oil, TBHQ Uses Emollient, carrier, dispersant in skin care, cosmetics, pharmaceuticals lubricating oil in industrial paints/coatings Regulatory EU, Japan approved Properties 1.5 red max. color bland odor Picco 1104 [Eastman]... 

Fig. 6. Schematic outline for manufacture of edible soybean oil products, where D = deodorization, W = winterization, and S = solidification (73).

Nagao, T., Kobayashi, T., Hirota, Y., Kitano, M., Kishimoto, N., Fujita, T., Watanabe, Y., and Shimada, Y. 2005. Improvement of a process for purification of tocopherols and sterols from soybean oil deodorizer distillate. J. Mol. Catal. B Enzym., 37, 56-62. 

Shimada, Y., Nakai, S., Suenaga, M., Sugihara, A., Kitano, M., and Tominaga, Y. 2000. Facile purification of tocopherols from soybean oil deodorizer distillate in high yield using lipase. /. Am. Oil Chem. Soc., 77,1009-1013. 

Wang, L., Du, W., Liu, D., Li, L., and Dai, N. 2005. Lipase-catalyzed biodiesel production from soybean oil deodorizer distillate with absorbent present in fert-butanol system. J. Mol Catal. B Enzym., 43, 29-32. 

The volatile peroxides, other oxidation decomposition products, and odiferous compounds form reduced-boiling point azeotropes with water in the steam, at high temperatures, 250-260°C/482-500°F, and very low absolute pressures ( 3 mbar). This is above the smoke point of soybean oil, but below the flash point, and oxygen must be excluded. Considerable heat bleaching of yellow-red carotenoids also occurs at this temperature. Typically the deodorization process requires 20-40 min after come-up time, uses 0.5-2.0 percent spaiged steam (the higher level if tocopherols are recovered), operates at between 2 and 4 mbar, and produces a product with about 0.03-0.05 percent FFA.143... 

Winterizing is not practiced so widely in hot countries and its application is restricted mainly to sunflower, maize, cotton, ohve, ricebran, and partially hydrogenated soybean oils. The feedstock of the winterizing plant is usually bleached oil, sometimes neutralized or deodorized oil. The winterizing process is conducted in four steps ... 

The values for the crude oil compare closely with those of other commercial oils, such as soybean oil, when produced according to good extraction practices. Chlorophylls and sulfur compounds levels are higher in canola oil compared with most other commodity oils. The deodorized oil data reflect good refining practice and are similar to the data obtained with other deodorized commodity oils processed for food applications. 

Cmde soybean oil contains about 1.9 ppm of Vitamin Ki or phylloquinone (55). This vitamin plays a role in blood coagulation and bone metabolism. During refining, some Vitamin Ki may be lost (56, 57), especially during deodorization. Hydrogenation of the fat converts some of the Vitamin Ki to 2, 3 -dihydrovitamin Kj (58). 

The preparation of high-purity tocopherols and phytosterols involves steps such as molecular distillation, adduct formation, liquid-liquid extraction, supercritical fluid extraction, saponification, and chromatography (175). The extraction of tocopherols from soybean oil deodorizer distillate by urea inclusion and saponification of free fatty acids resulted in good recovery of tocopherols (208). To improve the separation of sterols and tocopherols, Shimada et al. (209) used a lipase to esterify sterols with free fatty acids. Then the steryl esters and tocopherols were separated better by molecular distillation. Chang et al. (210) used supercritical fluid CO2 extraction to recover tocopherols and sterols from soybean oil deodorizer distillate. A patent by Sumner et al. (211) advocated treatment of the distillate with methanol to converted free fatty acids and other fatty acid esters to methyl esters that can then be removed by a stripping operation. Then separation of sterols and tocopherols could be carried out by molecular distillation. 

Refined, bleached, partially hydrogenated, winterized, and deodorized, pure soybean oil. 

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