5 research outputs found
Enhanced Physical and Oxidative Stabilities of Soy Protein-Based Emulsions by Incorporation of a Water-Soluble Stevioside–Resveratrol Complex
To
strengthen the effectiveness of resveratrol (RES) as a natural
antioxidant in food systems, this work attempted to enhance the water
solubility of RES by utilizing the solubilizing properties of stevioside
(STE) and investigated the effect of STE-solubilized RES (STE–RES)
incorporation on the stability of soy protein isolate (SPI)-based
emulsions. The physical properties and oxidative stability of SPI
emulsions with STE/STE–RES were evaluated. The water solubility
of RES increased with the increase of STE concentration up to its
critical micelle concentration, suggesting the solubilization of hydrophobic
RES in STE self-assembled micelles. STE micelles competitively adsorbed
at the oil–water interface with SPI, forming a mixed SPI and
STE interfacial layer, thus resulting in a decrease in particle size
and evident enhancement in the physical stability of SPI-based emulsions.
After the incorporation of STE–RES, SPI emulsions showed an
enhanced oxidative stability with reduced lipid hydroperoxides and
volatile hexanal. This improvement was believed to be mainly attributed
to the targeted migration of RES to the interface during the adsorption
of the STE–RES complex, as evidenced by high interfacial accumulation
of RES
Synergistic Foaming and Surface Properties of a Weakly Interacting Mixture of Soy Glycinin and Biosurfactant Stevioside
The adsorption of the mixtures of
soy glycinin (11S) with a biosurfactant
stevioside (STE) at the air–water interface was studied to
understand its relation with foaming properties. A combination of
several techniques such as dynamic surface tension, dilatational rheology,
fluorescence spectroscopy, and isothermal titration calorimetry (ITC)
was used. In the presence of intermediate STE concentrations (0.25–0.5%),
the weak binding of STE with 11S in bulk occurred by hydrophobic interactions,
which could induce conformational changes of 11S, as evidenced by
fluorescence and ITC. Accordingly, the strong synergy in reducing
surface tension and the plateau in surface elasticity for mixed 11S–STE
layers formed from the weakly interacting mixtures were clearly observed.
This effect could be explained by the complexation with STE, which
might facilitate the partial dissociation and further unfolding of
11S upon adsorption, thus enhancing the protein–protein and
protein–STE interfacial interactions. These surface properties
were positively reflected in foams produced by the weakly interacting
system, which exhibited good foaming capacity and considerable stability
probably due to better response to external stresses. However, at
high STE concentrations (1–2%), as a consequence of the interface
dominated by STE due to the preferential adsorption of STE molecules,
the surface elasticity of layers dramatically decreased, and the resultant
foams became less stable
Palladium-Catalyzed Formylation of Aryl Halides with <i>tert</i>-Butyl Isocyanide
A novel
palladium-catalyzed formylation of aryl halides with isocyanide
in the presence of Et<sub>3</sub>SiH has been demonstrated, which
provides a strategy toward important aldehydes with moderate to excellent
yield. The advantage of this reaction includes milder conditions,
convenient operation, lower toxicity, and wide functional group tolerance
Palladium-Catalyzed One-Pot Synthesis of Quinazolinones via <i>tert</i>-Butyl Isocyanide Insertion
A novel palladium-catalyzed three-component
reaction for the synthesis
of quinazolin-4Â(3<i>H</i>)-ones from readily available 2-aminobenzamides
and aryl halides via a palladium-catalyzed isocyanide insertion/cyclization
sequence has been developed. This methodology efficiently constructs
quinazolin-4Â(3<i>H</i>)-ones in moderate to excellent yields
with the advantages of operational simplicity
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 <i>trans</i> fats