Oil Recovery and Lecithin Fractionation from Wet Gums Obtained by Water Degumming of Soybean Oil

G.H. CRAPISTE; L.N. CECI; CONSTENLA, D.

Madrid

Congreso; 4 th Euro Fed Lipids Congress; 2006

Universidad Complutense de Madrid (UCM)

Oil Recovery and Lecithin Fractionation from Wet Gums Obtained by Water Degumming of Soybean Oil Guillermo H. CRAPISTE, Liliana N. CECI and Diana T. Constenla PLAPIQUI (Universidad Nacional del Sur-CONICET), Bahía Blanca, Argentina.   About 25,000,000 ton of soybeans are processed yearly in Argentina and consequently 4,850,000 ton of crude oil and 145,000 ton of sludge are produced during water degumming. An approximate quantity of 30,000 ton of oil and 40,000 ton of lecithin are lost with this sludge. The objectives of this study are the recovery of retained oil in wet gums and the separation and fractionation of lecithin. The quality of recovered oil for it insertion in the productive process was evaluated and the obtained lecithin composition was analysed. Five samples of wet gums obtained by water degumming of crude soybean oil collected in two industrial plants were used. The following procedures were employed: wet gum extraction with cold acetone and recovery of oil from acetone extract by evaporation and centrifugation (Method 1), wet gum dried at 60 °C under vacuum before the extraction with acetone (Method 2) and water elimination with hexane and ethanol before the extraction with cold acetone (Method 3). Polar compound composition in oils was determined by IR-HPSEC. Phospholipid composition in recovered oils and lecithin was analysed by UV-HPLC method. Higher yield of recovered oil was observed when Method 3 was used  (51.4-68,3 %).  The acidity values for recovered oils (until 3% as oleic acid) were some higher than that recommended for crude soybean oils (0.3-0.7 %) fundamentally when Methods 1 and 2 were applied. These results suggest that the wet gum conservation is crucial step to            avoid that hydrolytic process result accelerated. Important oxidative processes not were observed according to peroxide and anisidine values. The oil recovered by Method 2 had phosphatidic acid relative percentages higher than those obtained by Method 1. Direct extraction with acetone from wet gum according to Method 1 promotes the dragging of hydratable phospholipids, phosphatidylcholine and phosphatidylinositol. The analysis of contents and composition of polar compounds in recovered oils showed that the level of thermal oxidation was not significant and it was comparable to hydrolytic degradation.