Na-Na Wu

Protein-Based Pickering Emulsion and Oil Gel Prepared by Complexes of Zein Colloidal Particles and Stearate

This paper describes the successful preparation of a protein-based Pickering emulsion, with superior stability against both coalesence and creaming, through a novel strategy of facilitating the formation of protein particles and small molecular weight surfactant complexes; these complexes are able to overcome multiple challenges including limited solubility, poor diffusive mobility, and low interfacial loading. Soluble complexes of water-insoluble corn protein, zein colloidal particles, and surfactant sodium stearate (SS) were fabricated by simple ultrasonication. Gel trapping technology combined with SEM was applied to characterize the adsorbed particles monolayer at the oil-water interface; results revealed an enhanced adsorption and targeted accumulation of zein particles at the interface with the increase of SS concentration. Partial unfolding of zein particles modified by SS above its critical complexation concentration triggered the aggregation and close packing of particles at the oil-water interface and endowed a steric barrier against the coalescence of oil droplets. Moreover, protein-based oil gels without oil leakage were obtained by one-step freeze-drying of the zein-stabilized Pickering emulsions, which could be developed to a viable strategy for structuring liquid oils into semisolid fats without the use of saturated or trans fats.

In vitro assessment of the bioaccessibility of fatty acids and tocopherol from soybean oil body emulsions stabilized with ι-carrageenan.

The present investigation aimed to expand the knowledge of the in vitro bioaccessibility of fatty acids and tocopherol from natural soybean oil body emulsions stabilized with different concentrations of ι-carrageenan. Several physicochemical parameters including proteolysis of the interfacial layer, interfacial composition, and microstructure were evaluated with regard to their impact on the bioaccessibility of fatty acids and tocopherol. Results from simulated human digestion in vitro indicated that the bioaccessibility of total fatty acids and tocopherol decreased (62.7-8.3 and 59.7-19.4%, respectively) with the increasing concentration of ι-carrageenan. During the in vitro digestion procedure, ι-carrageenan affected physicochemical properties of the emulsions, thereby controlling the release of fatty acids and tocopherol. These results suggested that soybean oil body emulsions stabilized with ι-carrageenan could provide natural emulsions in foods that were digested at a relatively slow rate, the important physiological consequence of which might be increasing satiety.

Formation of Complex Interface and Stability of Oil-in-Water (O/W) Emulsion Prepared by Soy Lipophilic Protein Nanoparticles

A lipophilic protein nanoparticle (LPP) was fabricated by ultrasonication of the soy lipophilic protein (LP), which contains hydrophobic proteins and phospholipids. This LPP (Rh = 136 ± 0.8 nm, ζ-potential = -20 mV, pH 7.0) had an improved dispersibility and acted as an emulsifier. The oil/water (O/W) emulsion stabilized by this LPP exhibited superior physical stability over long-term storage (8 weeks), during a stress storage test (200 mM NaCl addition and heating at 90 °C), and in the presence of Tween 20 (1.0-4.0 wt %), in contrast to those emulsions stabilized by β-conglycinin and glycinin. Langmuir-Blodgett method and interface pressure determination revealed that LPP formed rigid and rough granular film at air/water interface. The excellent stability of emulsions stabilized by LPP highlights the synergic effect between hydrophobic proteins and phospholipids. These findings suggest that the complexes of hydrophobic protein aggregates and biosurfactant could form a stable interface which could be developed into a novel strategy to fabricate a stable food emulsion.

Prevention of retinoic acid‐induced osteoporosis in mice by isoflavone‐enriched soy protein

BACKGROUND A novel soy protein aggregate enriched with isoflavones (SPA-IS), a mixture of soy protein and isoflavones (Mix), isoflavones (IS), and the soy protein were obtained to investigate the preventive effects on osteoporosis induced by retinoic acid in Kunming mice. RESULTS The serum osteocalcin levels in the Mix and SPA-IS groups decreased compared with the model group (mice showing retinoic acid-induced osteoporosis) (P < 0.05). The trabecular analysis results showed an increased preventive effect of the SPA-IS group over the Mix group, the IS group, and the soy protein group. The results of both left tibial maximum load and the 4th lumbar structural strength differ between the IS and the SPA-IS groups. CONCLUSION The SPA-IS exhibited obvious oestrogenic activities on retinoic acid-induced osteoporosis in Kunming mice compared to Mix, IS, and soy protein. The results suggest that there is a potential use for SPA-IS in the treatment of osteoporosis induced by intake of retinoic acid. The improvement of bone indicators might be attributed to the formation of aggregate particles and the improvement of IS solubility.

Characterization and Interfacial Behavior of Nanoparticles Prepared from Amphiphilic Hydrolysates of β-Conglycinin–Dextran Conjugates

Amphiphilic graft copolymers were prepared from β-conglycinin-dextran conjugates hydrolyzed by trypsin at a degree of hydrolysis (DH) of 2.2%. Nanoparticles were prepared from β-conglycinin, β-conglycinin-dextran conjugates (CDC), and amphiphilic hydrolysates of β-conglycinin-dextran conjugates at DH 2.2% (CDCH) by a desolvation method. All of the nanoparticle samples exhibited spherical structures, as evidenced by dynamic light scattering, transmission electron microscopy, and small-angle X-ray scattering. The nanoparticles prepared from amphiphilic hydrolysates of β-conglycinin-dextran conjugates at DH 2.2% (CDCHN) exhibited higher interfacial pressure and dilatational modulus after long-term absorption at the oil-water interface compared with nanoparticles prepared from β-conglycinin (CN) and β-conglycinin-dextran conjugates (CDCN). This might be mainly associated with the higher surface hydrophobicity of CDCHN, which enhanced adsorption and intermolecular interactions of nanoparticles in the adsorbed layer.