Emulsifiers from White Beans: Extraction and Characterization

Abstract

This paper studies the emulsification capacity of aqueous extracts from white beans and reports the relations between the composition and structure of the extracts’ macromolecular components and their exerted emulsification ability. The extracts comprise of three distinct populations: one of large (few MDa) polysaccharides, proteins (tens of kDa), and smaller molecular entities (oligopeptides and oligosaccharides, polyphenols, and salts, among other molecules); the proteins and the smaller molecules adsorb onto oil–water interfaces, providing some emulsification capacity at pH 3 and adequate emulsification at pH 7. Unabsorbed polysaccharides, such as starch, cause depletion flocculation. Pickering phenomena are involved in the stabilization mechanism. The findings are supported by SEC–MALLS/UV, confocal microscopy, zeta potential measurements, and FT–IR data. A discussion is made on the particular attributes of each population in emulsion stability, on their relevance to culinary practice, and in their potential as replacers of artificial emulsifiers.

Keywords

• white beans
• emulsions
• emulsifiers
• Pickering emulsifiers
• interfacial tension
• size exclusion chromatography