ORIGINAL ARTICLE Legume Protein Isolates for Stable Acidic Emulsions Prepared by Premix Membrane Emulsification Yakoub Ladjal Ettoumi 1,2 & Claire Berton-Carabin 3 & Mohamed Chibane 4 & Karin Schroën 3 Received: 23 October 2016 /Accepted: 16 January 2017 # Springer Science+Business Media New York 2017 Abstract Proteins originating from dry legumes are not that much used in food formulations, yet, they are interesting compo- nents from a sustainability point of view, and could have interest- ing functional properties, e.g. for emulsion preparation. Therefore, this work focuses on the potential of the water soluble part of pea, chickpea and lentil protein isolates under acidic emul- sions (pH 3.0) using a novel mild technique: premix membrane emulsification. Pea proteins (PP) and chickpea proteins (CP) low- er the interfacial tension in the same way as whey protein isolate (WPI), which suggests that they could facilitate emulsion droplet formation similarly as WPI, while lentil proteins (LP) are slightly less effective. It is possible to make oil-in-water (O/W) emulsions with an average droplet diameter (d 4,3 ) of ~5 μm after 5 cycles in the premix system. The droplet size distribution of the emulsions remained constant during one day of storage, indicating that le- gume proteins are able to form and kinetically stabilize O/W emulsions. CP and PP exhibited emulsifying properties comparable to those of WPI, whereas LP is slightly less efficient, therewith indicating the great potential and that pea and chickpea protein isolates hold as emulsifiers in acidic food formulations. Keywords Legume proteins . Premix membrane emulsification . Emulsifiers . oïl-in-water emulsions . Interfacial tension Introduction Emulsions are important for food, pharmaceutical and cosmetic products; commonly cited food emulsions include ice cream, mayonnaise, salad dressings, soups, sauces, which are all supplied to global markets in large quantities [ 1]. This is rather remarkable since emulsions are thermodynamically unstable [ 2], and to keep them stable for an appreciable time, both the preparation method and the emulsion ingredients need to be chosen carefully. Nowadays, consumer demands originating from health con- cerns, allergenicity, religious limitations (Halal) and vegetarianism have increased the interest of the food industry in plant proteins compared to animal-based proteins [ 3, 4]. Maybe even more im- portantly, plant proteins are more sustainable compared to animal based proteins (dairy), and this is our main interest in their use [ 5]. Soybean and wheat proteins are mostly used although other vegetable protein sources are getting more attention of re- searchers, food manufacturers and consumers [ 6–10]. Amongst these are dry legumes that are extensively grown in different parts of the world. Legume proteins are abundantly and commercially available at an attractive price [ 11], and are nutritional and func- tional food ingredients [ 12], containing well balanced amino acids profiles, with especially a high content of lysine [13]. Furthermore, they have been reported to stabilize emulsions at neutral pH [9], and may be used without chemical modifications; Electronic supplementary material The online version of this article (doi:10.1007/s11483-017-9471-x) contains supplementary material, which is available to authorized users. * Yakoub Ladjal Ettoumi yakoblajel@hotmail.fr 1 Département des Sciences Alimentaires, FSNV, Université Abderahman Mira, Bejaia, Route Targa Ouzemour, Bejaia 06000, Algérie 2 Ecole Supérieure en Sciences de l’Aliment et des Industries Agroalimentaires (ESSAIA, Ex EPSNV-Alger), Avenue Ahmed Hamidouche Route de Beaulieu, El Harrach, 16200 Alger, Algérie 3 Food Process Engineering Group, Wageningen University, Bornse Weilanden 9, 6708, WG Wageningen, The Netherlands 4 Laboratoire de Gestion et Valorisation des Ressources Naturelles Assurance Qualité, Université Akli Mohand Oulhadj de Bouira, 10000 Bouira, Algérie Food Biophysics DOI 10.1007/s11483-017-9471-x