Solubilization and conformational behavior of Zein in aqueous solution of dodecyldimethylethylammonium bromide (DDAB)

Interaction behaviors and structural characteristics of zein/NaTC nanoparticles

Bile salts are biosurfactants distributed in the human gastrointestinal tract, which can significantly influence the structure and functions of orally administrated components.

Interactions between surfactants and the skin - Theory and practice

One of the primary causes of skin irritation is the use of body wash cosmetics and household chemicals, since they are in direct contact with the skin, and they are widely available and frequently used. The main ingredients of products of this type are surfactants, which may have diverse effects on the skin. The skin irritation potential of surfactants is determined by their chemical and physical properties resulting from their structure, and specific interactions with the skin. Surfactants are capable of interacting both with proteins and lipids in the stratum corneum. By penetrating through this layer, surfactants are also able to affect living cells in deeper regions of the skin. Further skin penetration may result in damage to cell membranes and structural components of keratinocytes, releasing proinflammatory mediators. By causing irreversible changes in cell structure, surfactants can often lead to their death. The paper presents a critical review of literature on the effects of surfactants on the skin. Aspects discussed in the paper include the skin irritation potential of surfactants, mechanisms underlying interactions between compounds of this type and the skin which have been proposed over the years, and verified methods of reducing the skin irritation potential of surfactant compounds. Basic research conducted in this field over many years translate into practical applications of surfactants in the cosmetic and household chemical industries. This aspect is also emphasized in the present study.

Self-Assembly of Oleyl Bis(2-hydroxyethyl)methyl Ammonium Bromide with Sodium Dodecyl Sulfate and Their Interactions with Zein

Surface tension and aggregation behavior in an aqueous solution of the mixture of cationic surfactant oleyl bis(2-hydroxyethyl)methylammonium bromide (OHAB) and anionic surfactant sodium dodecyl sulfate (SDS) have been studied by surface tension, conductivity, turbidity, zeta potential, isothermal titration microcalorimetry (ITC), cryogenic transmission electron microscopy (Cryo-TEM), and dynamic light scattering. The mixture shows pretty low critical micellar concentration and surface tension, and successively forms globular micelles, unilamellar vesicles, multilamellar vesicles, rod-like micelles, and globular micelles again by increasing the molar fraction of OHAB from 0 to 1.00. The cooperation of hydrophobic interaction between the alkyl chains, electrostatic attraction between the headgroups as well as hydrogen bonds between the hydroxyethyl groups leads to the abundant aggregation behaviors. Furthermore, the solubilization of zein by the OHAB/SDS aggregates and their interactions were studied by ITC, total organic carbon analysis (TOC), and Cryo-TEM. Compared with pure OHAB or pure SDS solution, the amount of zein solubilized by the OHAB/SDS mixture is significantly reduced. It means that the mixtures have much stronger abilities in solubilizing zein. This result has also been proved by the observed enthalpy changes for the interaction of OHAB/SDS mixture with zein. Mixing oppositely charged OHAB and SDS reduces the net charge of mixed aggregates, and thus, the electrostatic attraction between the aggregates and zein is weakened. Meanwhile, the large size of the aggregates may increase the steric repulsion to the zein backbone. This work reveals that surfactant mixtures with larger aggregates and smaller CMCs solubilize less zein, suggesting how to construct a highly efficient and nonirritant surfactant system for practical use.

Physico-Chemical Studies of Glycine, L-Alanine, L-Phenylalanine and Glycylglycine in Aqueous Triton X-100 at Different Temperatures

The densities, ρ and viscosities, η of glycine (Gly), L-alanine (Ala), L-phenylalanine (Phe) and glycylglycine (Gly-Gly) in aqueous Triton X-100 (TX-100) solutions have been measured as a function of amino acid/peptide concentration at 298.15, 303.15, 308.15 and 313.15 K. The experimental data have been utilized to evaluate various thermodynamic parameters, viz., apparent molar volumes, V 2, partial molar volumes at infinite dilution, V 0 2, partial molar isobaric expansibilities, ϕ 0 2, partial molar volumes of transfer, Δ tr V 0 2 and A and B-coefficients of viscosity, respectively. The hydration numbers have also been calculated. The results have been discussed in terms of interactions taking place in the present systems. The structure-making/-breaking ability of the solute (amino acid/peptide) in the presence of surfactant, Triton X-100 has also been considered.

Intrinsic Tween 20 improves release and antilisterial properties of co-encapsulated nisin and thymol

Antimicrobial delivery systems have been proposed as potential solutions to improve effectiveness of antimicrobials in food matrixes by shielding antimicrobials from contacting food matrix components and releasing them continuously. In this work, spray-dried capsules were produced from zein solutions with the same concentrations of nisin and thymol but with varying Tween 20 contents for characterization of release kinetics of antimicrobials and antilisterial properties. At intermediate levels of Tween 20, sustained and more complete release of antimicrobials was observed at pH 6.0 and 8.0. Most capsule samples were more effective than free antimicrobials against Listeria monocytogenes in 2% reduced fat milk, and the best capsule treatment reduced the bacterial population by 2 log CFU/mL more than comparable free antimicrobials after 4 h incubation at 25 °C. Our work demonstrated that nonionic surfactant can be conveniently used to modulate characteristics of delivery systems to effectively improve antimicrobial functions in food systems.