Functional properties of soybean and lupin protein concentrates produced by ultrafiltration‐diafiltration

Abstract

Abstract 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.