Novel pickering high internal phase emulsion gels stabilized solely by soy β-conglycinin. (March 2019)

• Record Type: Journal Article
• Authors: Xu, Yan-Teng; Liu, Tong-Xun; Tang, Chuan-He
• Is Part Of: Food hydrocolloids. Volume 88(2019)
• Page Start: 21
• Page End: 30
• Publication Date: 2019-03
• Subjects: Soy β-conglycinin -- High internal phase emulsions (HIPEs) -- HIPE gels -- Pickering stabilizer -- Bridged emulsions; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2018.09.031
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: There is fast increasing interest in the development of food-grade high internal phase emulsions (HIPEs). In the work, we reported that native soy β -conglycinin ( β -CG; a major 7S globulin in soybeans) could perform as an outstanding Pickering-type stabilizer for oil-in-water HIPEs. The protein concentration in the continuous phase ( c ) for the formation of homogenous and gel-like HIPEs could be as low as 0.2 wt%; and increasing the c from 0.2 to 1.0 wt% led to a progressive decrease in droplet size, but a progressive increase in stiffness of the HIPEs. The fabricated HIPEs at low c values (e.g., 0.2–0.5 wt%) were a kind of HIPE gels in essence with a gel network that could not be disrupted by 6 M urea, while the HIPE at c = 1.0 wt% was a highly concentrated emulsion that could be diluted by water. All the HIPEs at c values of 0.2–1.0 wt% were extremely stable against heating (at 100 °C for 15 min), or an elongated storage up to 60 days, but they were very prone to a freeze-thawing treatment. The freeze-thawed HIPEs could be repeatedly recovered back to a similar state to the untreated ones, when subject to another emulsification, indicating an extraordinary temperature-responsiveness. The β -CG molecules suffered a structural dissociation at the quaternary conformational level into separate subunits when adsorbed at the oil-water interface. The dissociated subunits from adsorbed β -CG showed a similar tertiary and secondary conformation to that of native β -CG, confirming the Pickering-nature of these subunits. All the HIPEs exhibited a surface coverage of around 60% in regard to the subunits of β -CG. The findings would be of importance not only for extending the knowledge about the Pickering stabilization of HIPEs by native oligomeric globulins, but also for the development of novel, eco-friendly and sustainable HIPEs for food, cosmetic and medicine formulations. Graphical abstract: Image Highlights: Native β -conglycinin ( β -CG) was demonstrated to be an outstanding Pickering nanostabilizer for HIPEs. A kind of HIPE gels could be facilely formed at low concentrations (0.2–0.5 wt%). The HIPEs or HIPE gels exhibited extraordinary stability against heating and storage. The HIPEs were susceptibile to freeze-thawing, but could be recovered by another homogenization. Dissociated subunits of β -CG at the interface were the factual stabilizers for the HIPEs.