It is technically feasible to extract protein with desirable emulsifying and heat stability properties from dried alfalfa leaves; however, the dried form may not be a practical starting material for protein production, given the difficulty of achieving high yields and high-purity protein product. © 2016 Society of Chemical Industry.

Ultrafiltration followed by diafiltration (UF-DF) was evaluated for the production of protein products from partially defatted soybean meal or undefatted lupin (Lupinus albus L.2043N) meal. This study determined the effects of UF-DF on functional properties of the extracted proteins and compared the results with those of protein prepared by acid-precipitation (AP). UF-DF produced only protein concentrates (73% crude protein, dry basis, db), while AP produced protein isolates (about 90% crude protein, db). Soybean protein produced by UF-DF showed markedly higher values for solubilities up to pH 7.0, surface hydrophobicity index, emulsion activity index, and foaming capacity than did the AP soybean protein. UF-DF soy protein was also the most heat-stable among all protein samples tested. With lupin proteins, only the surface hydrophobicity and emulsion activity indices were significantly improved by using UF-DF. 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. UF-DF did not produce a comparable improvement in functional properties of lupin proteins as it did for soybean protein.The Clean Air Act, which limits emissions of volatile organic compounds and other hazardous air pollutants, has spurred the utilization of mechanical extraction processes in the oilseed industry (1). One such solvent-free process is extrusion-expelling (E-E), a simple and relatively inexpensive operation (2) that has produced soybean oil of such quality that only minimal refining will be required (3). The resulting meal has higher oil content than what is found in meal produced from traditional solvent extraction (2), but E-E meal is considered as a higher energy source for livestock feed (1). Because E-E does not use desolventizing and drying, the meal is also presumed to have better functional properties, which would make it possible to use E-E meal for the production of the higher-value flours, concentrates, or isolates. Heywood et al. (4) prepared low-fat soy flours from E-E meal and found them to possess good solubilities (at pH values less than and greater than 4), emulsifying and foaming properties, and water-and fat-binding capacities. No study has yet been reported on the preparation and quality of concentrates or isolates from E-E meal.The present study explores ultrafiltration (UF) as a means of producing protein concentrates or isolates from E-E soybean meal. UF is a pressure-driven membrane process that has gained wide acceptance in protein bioseparations (5). It has a broad variety of applications, but it is used mainly for concentration, desalting, clarification, and fractionation (5). Sessa (6) recently produced peroxidase and Bowman-Birk inhibitor concentrates from soybean hulls by using UF, followed by discontinuous diafiltration (DF), a membrane-based method that removes low M.W. solutes such as salts while continuously replacing the solvent lost with the permeate (5). Both peroxidase and Bowman-Birk inhibitor are valua...

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