In this work the foaming ability of white lupin protein isolates was investigated in order to evaluate the potential use of these isolates as functional additives in food products and to find a vegetable alternative to egg-white foams (Raymundo et al., 1998).
Lupinus albus protein isolate, modified in order to improve its foaming ability, was tested. Thermal denaturation, chemical treatment (acylation) and enzymatic hydrolysis (with vegetal proteases) were used, and the best results were obtained by using an optimised thermal denaturation method. A series of additives was tried out in order to further improve foam stability; xanthan gum gave the best results. Prior heat treatment of the protein and the conditions under which foam was generated were optimised using response surface methodology. Texture and microstructure of the optimised lupin foam were objectively evaluated. The lupin foam, when boiled in water for 5 min became very similar in texture and microstructure to uncooked egg-white foams. This shows, therefore, some promise as a substitute of the latter for products like fruit and chocolate “mousses”, with the advantage of being able to withstand heat treatments.
References
Raymundo, A., Empis, J. & Sousa, I. White lupin protein isolate as a foaming agent. Z Lebensm Unters Forsch 207, 91–96 (1998). (Article)
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