Separating Oil from Aqueous Extraction Fractions of Soybean

Center for Crops Utilization Research, Iowa State University, Ames, IA 50011-1061, USA
Journal of the American Oil Chemists' Society (Impact Factor: 1.54). 08/2007; 84(8):785-792. DOI: 10.1007/s11746-007-1090-0


Previous research has shown that enzyme-assisted aqueous extraction processing (EAEP) extracts 88–90% of the total soybean
oil from extruded full-fat soy flakes into the aqueous media, which is distributed as cream (oil-in-water emulsion), skim,
and free oil. In the present work, a simple separatory funnel procedure was effective in separating aqueous skim, cream and
free oil fractions allowing mass balances and extraction and recovery efficiencies to be determined. The procedure was used
to separate and compare liquid fractions extracted from full-fat soy flour and extruded full-fat soy flakes. EAEP extracted
more oil from the extruded full-fat soy flakes, and yielded more free oil from the resulting cream compared to unextruded
full-fat soy flour. Dry matter partitioning between fractions was similar for the two procedures. Mean oil droplet sizes in
the cream and skim fractions were larger for EAEP of extruded flakes compared to non-enzymatic AEP of unextruded flour (45
vs. 20μm for cream; 13 vs. 5μm for skim) making the emulsions from EAEP of extruded flakes less stable. All major soy protein
subunits were present in the cream fractions, as well as other fractions, from both processes. The cream could be broken using
phospholipase treatments and 70–80% of total oil in the extruded full-fat flakes was recovered using EAEP and a phospholipase
de-emulsification procedure.

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Available from: Buddhi P. Lamsal, Mar 13, 2014
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    • "The major obstacle to commercial adoption of AEP was the low oil yields. The inefficient extraction was caused by difficulties in rupturing cell walls and releasing oil directly into water in the form of stable cream (Rosenthal et al., 1996; Lamsal and Johnson, 2007). The comminution of oilseeds which have high oil and high protein contents have always been a huge problem when using AEP. "
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    ABSTRACT: A three cylindrical roll crusher was used in this study to solve the comminution problem and to improve oil and protein yields in aqueous extraction processing (AEP) of peanuts. We combined confocal laser scanning microscopy (CLSM) and particle size distribution analysis to investigate the effect of different peanut processing material on oil and protein extraction. A proper roasting treatment (150 °C) is beneficial to oil extraction yield. However, the protein yield has been declining from 84.33% to 51.40% with the increase of roasting temperature from (130 °C-210 °C). The optimal average particle size of peanut paste in AEP was 15.2 μm which could hardly find intact oil bodies by CLMS. Nevertheless, the remained intact of protein body still could be found in insoluble fraction. In AEP, highest free oil yield (92.2%) was achieved with roasted peanut (150 °C, 20 min) using 1: 5 solid to liquid ratio (twice ground peanut pastes/water), pH 9, 60 °C for 2 h and demusification by adding 0.5% (w/w) Protex 50FP at pH 4.5 and incubating at 50 °C for 2 h. Without roasting treatment, the oil contents of insoluble and residual cream fractions from AEP were highly correlated with their protein contents (R2 = 0.8724, 0.9178, respectively). Additionally, the exposure of interior hydrophobic groups of peanut protein adhere more oil to the protein body surface, which may have led to increment in the oil content of insoluble fraction.
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    • "2.9. Gravimetric analysis of extracted oils Petroleum ether (PE 40e60 C) was used to dilute the free oil after microbial extraction to prevent oil loss due to small sample used [10] [11]. The free oil on the surface of the liquid in the centrifuge tube was diluted with 3 ml petroleum ether without shaking (to prevent oil extraction from emulsion) over a minimum of 6 h. "
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    ABSTRACT: A traditional Java method of coconut oil extraction assisted by paddy crabs was investigated to find out if crabs or crab-derived components can be used to extract oil from Jatropha curcas seed kernels. Using the traditional Java method the addition of crab paste liberated 54% w w−1 oil from grated coconut meat. Oil extraction using crab paste carried out under controlled temperatures and in the presence of antibiotics showed that enzymes from crab played a dominant role in liberating oil from grated coconut meat and aqueous J. curcas kernel slurries when incubated at 30 °C or 37 °C. However, at higher temperature (50 °C), thermophilic bacterial strains present inside crabs played a significant role in the extraction of oil from both oilseeds tested. A thermophilic bacterial strain isolated from crab paste and identified based on 16s rRNA sequence as Bacillus licheniformis strain BK23, when added as starter culture, was able to liberate 60% w w−1 oil from aqueous J. curcas kernel slurry after 24 h at 50 °C. Further studies of BK23 and extraction process optimization are the challenges to improve Jatropha oil extraction yield and process economy
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    ABSTRACT: The effects of two commercial endoproteases (Protex 6L and Protex 7L, Genencor Division of Danisco, Rochester, NY, USA) on the oil and protein extraction yields from extruded soybean flakes during enzyme-assisted aqueous extraction processing (EAEP) were evaluated. Oil and protein were distributed in three fractions generated by the EAEP: cream+free oil, skim and insolubles. Protex 6L was more effective for extracting free oil, protein and total solids than Protex 7L. Oil and protein extraction yields of 96 and 85%, respectively, were obtained using 0.5% Protex 6L. Enzymatic and pH treatments were evaluated to de-emulsify the oil-rich cream. Cream de-emulsification generated three fractions: free oil, an intermediate residual cream layer and an oil-lean second skim. Total cream de-emulsification was obtained when using 2.5% Protex 6L and pH 4.5. The extrusion treatment was particularly important for reducing trypsin inhibitor activity (TIA) in the protein-rich skim fraction. TIA reductions of 69 and 45% were obtained for EAEP skim (the predominant protein fraction) from extruded flakes and ground flakes, respectively. Protex 6L gave higher degrees of protein hydrolysis (most of the polypeptides being between 1,000 and 10,000Da) than Protex 7L. Raffinose was not detected in the skim, while stachyose was eliminated by α-galactosidase treatment.
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