Novel nanoparticles from insoluble soybean polysaccharides of Okara as unique Pickering stabilizers for oil-in-water emulsions

• Published in: Food hydrocolloids Vol. 94; pp. 255 - 267
• Main Authors: Yang, Tao, Liu, Tong-Xun, Li, Xiu-Ting, Tang, Chuan-He
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2019
• Subjects: Emulsification performance; Insoluble soybean polysaccharides; Nanoparticles; Okara; Pickering emulsions; Ultrasonication; Nanoparticles; Ultrasonication; Pickering emulsions; Emulsification performance; Insoluble soybean polysaccharides; Okara
• ISSN: 0268-005X; 1873-7137
• DOI: 10.1016/j.foodhyd.2019.03.035

The development of biocompatible Pickering stabilizers for oil-in-water emulsions has attracted fast increasing interests, due to their potential applications in food and pharmaceutical formulations. This work reports that a kind of novel nanoparticles to perform as outstanding Pickering stabilizers can be facilely fabricated from insoluble soybean polysaccharides (ISP) of Okara (a byproduct of soybean processing) by a high power ultrasonication. The ultrasonication resulted in breakdown of polysaccharide-based fibres in the ISP, and subsequently, formation of nanoparticles with sizes of 127–221 nm. The nanoparticles were mainly composed of polysaccharides and proteins, possessing a lower crystallinity of cellulose (relative to ISP) and good interfacial adsorption at oil-water interface. They were demonstrated to exhibit an excellent emulsification performance and a high tendency to form a gel-like network in the Pickering emulsions. Increasing the particle concentration and/or oil volume fraction was favorable for the creaming stability of the emulsions. Most of the droplets in the emulsions at higher particle-to-oil ratios were present in a more flocculated state, which was maintained by the hydrophobic interactions, as well as a bridging particle monolayer (with two droplets sharing the same monolayer). Interestingly, a portion of fine oil droplets with sizes <0.1 μm were entrapped within the flocculated structure consisting of large droplets with sizes at around 8 μm, which might largely account for the excellent emulsification performance of these nanoparticles. The findings would be of importance not only for the development of a kind of food grade nanoparticles to perform as outstanding Pickering stabilizers for the emulsions, but also for providing a strategy for the highly-added-value utilization of Okara. [Display omitted] •Nanoparticles from insoluble polysaccharides of Okara were facilely fabricated by ultrasonication.•The nanoparticles were mainly composed of polysaccharides and proteins.•The nanoparticles exhibited an excellent emulsification performance and Pickering stabilization.•Increasing the particle concentration and/or oil fraction favored the emulsion creaming stability.•A new emulsion stabilization mechanism was proposed.