Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2004
Publication Date: May 9, 2004
Citation: Hojillaevangelist, M.P., Sessa, D.J., Mohamed, A. 2004. Functional properties of soybean and lupin protein concentrates produced by ultrafiltration/diafiltration [abstract]. American Oil Chemists Society. p. 117. Technical Abstract: Ultrafiltration, followed by diafiltration (UF-DF), was evaluated for the production of protein concentrates from full-fat soybean or lupin (Lupinus albus L.2043N) meal. The effects of this approach on several functional properties of the extracted protein products were determined in this study and compared with those of protein extracts prepared by the classic acid-precipitation (AP) method. Protein samples produced by UF-DF from either meal contained 73% crude protein (dry basis, db), while the AP-samples had markedly higher protein content (about 90% db). Solubilities of the UF-DF soybean protein samples improved progressively from pH 4.0 to pH 7.0 and were considerably greater than the values obtained for their acid-precipitated counterparts. The AP-soy protein samples were totally soluble at pH 10.0, while no further increase in solubilities were detected for the UF-DF soy protein samples at pH greater than 7.0. With the lupin protein, similar amounts of soluble fractions were determined for both the UF-DF and AP samples at each of the pH values tested, indicating that the method of preparation produced no major difference in their solubility behavior. UF-DF soy protein produced more foam than did the AP-soy protein, but its foam was slightly less stable than that of the latter. The lupin protein samples had similar foam capacities (100 mL in 1 min), but the foams collapsed very quickly, unlike the soy protein foams. Emulsifying capacity of the UF-DF soy protein was 76% more than that of the AP soy protein, but emulsion stabilities were equal. Similar results were observed in the emulsifying properties of the lupin protein samples. Surface hydrophobicity for UF-DF soy protein was significantly greater (nearly double) than that of AP soy protein, while the opposite result was obtained for the lupin protein. Both soy protein samples were markedly more heat-stable than the lupin protein extracts, with the UF-DF soy protein being the most heat-stable of all the samples (<10% protein loss on heating). The soy proteins also formed good gels after heating and cooling, while the lupin protein samples did not gel. UF-DF generally had no adverse effects on, and in most cases even improved, the functional properties of soy protein concentrate produced by this method.