Densities and heat capacities of water−substrate, water−cyclodextrin, and water−substrate−cyclodextrin systems were determined at 298 K. The substrates studied are sodium n-alkanecarboxylates (C n COONa) (from sodium acetate to sodium decanoate) and the cyclodextrins are hydroxypropyl-α-cyclodextrin (HP-α-CD), hydroxypropyl-β-cyclodextrin, (HP-β-CD), hydroxypropyl-γ-cyclodextrin (HP-γ-CD) and β-cyclodextrin (β-CD). The apparent molar volumes and heat capacities of C n COONa in water were calculated as functions of concentration. The standard partial molar properties agree with those obtained by using the additivity rule. HP-β-CD essentially does not affect the thermodynamic properties of C1COONa and C2COONa. Contrarily, the formation of the inclusion complex between cyclodextrin and substrate modifies the apparent molar properties. From the standard partial molar properties of the substrate in pure water and in water + HP-β-CD mixtures and literature values for the equilibrium constant for the inclusion complex formation, the standard partial molar properties of the complex ( ) were calculated. The increase of with the number of carbon atoms in the alkyl chain (n) is consistent with the solubilization of methylene groups in the hydrophobic cavity of the cyclodextrin and the expulsion of some water molecules from the cavity. To explain the dependence of on n, conformational effects are also invoked. Studies performed as functions of cyclodextrin concentration evidence that micellization occurs provided that all the cyclodextrin is almost complexed and that the dispersed surfactant concentration equals its critical micelle concentration in water. Data in HP-α-CD, HP-β-CD, HP-γ-CD, and β-CD indicate that the size cavity of the cyclodextrin strongly affects the thermodynamics of the inclusion complex formation while the nature of the hydrophilic shell of the cyclodextrin does not.

Conductivity, density, heat capacity, enthalpy of dilution, and osmotic coefficient measurements of water−sodium perfluorooctanoate (NaPFO)−sodium dodecanoate systems were carried out as functions of the surfactants' total molality (m t) at different mole fractions (X NaPFO). From conductivity data, the critical micelle concentration (cmc) and the degree of ionization (β) of the micelles were derived. The cmc's of the micelles are higher than those of the pure surfactants while β depends linearly on X NaPFO. At a given mole fraction, the apparent molar volume (V Φ) and heat capacity (C Φ) of the mixture increases and decreases monotonically with m t, respectively. From data in the premicellar region, the standard (infinite dilution) partial molar properties (Y o) of the mixtures were calculated for both volume and heat capacity. Y o depends linearly on X NaPFO according to the ideal behavior. From data in the postmicellar region, the excess properties (Y exc) for the mixed micelles formation from pure micelles were calculated. The values of the excess volumes and heat capacities are positive and negative, respectively, in the whole range of composition. The excess free energy (G exc) is negative while both enthalpy and entropy are positive. On the basis of the pseudophase transition model and experimental evidences, the G exc vs composition profile was derived. This profile indicates the presence of a critical point for 0.4 ≤ X NaPFO ≤ 0.6. According to this approach, G exc was calculated for some mixtures. It turned out that sodium dodecanoate and sodium dodecyl sulfate micelles are miscible in the whole range of composition while ammonium perfluorononanoate (NH4PFN) and ammonium dodecyl sulfate micelles are partially miscible, and the coexistence of the two mixed micelles pseudophases occurs in the range 0.43 ≤ X NH 4 PFN ≤ 0.75. In the case of the sodium decyl sulfate−sodium perfluorooctanoate system, only a critical point is present.

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Enthalpies of dilution and osmotic coefficients of sodium dodecyl sulfate (NaDS) and dodecyltrimethylammonium bromide (DTAB) in water + 18-crown-6 ether (CR) and water + β-cyclodextrin (CD) at a fixed cosolvent concentration were measured at 298 and 310 K, respectively, as functions of the surfactant concentration (m S). Enthalpies of transfer ΔH (W → W + S) of CR (0.03 m) from water to NaDS and DTAB aqueous solutions as functions of m S were also determined at 298 K. From the enthalpies of dilution the apparent (LΦ,S) and partial (L2,S) molar relative enthalpies of both surfactants were calculated. Despite CR forms inclusion complexes with the anionic surfactant only, the L2,S vs m S profiles are similar and the enthalpies of micellization are lower than those in water by about −5 kJ mol-1. In the case of CD as a cosolvent, the L2,S vs m S profile for DTAB is similar to that for NaDS in the postmicellar region but very different in the premicellar one. The trends in the premicellar region are discussed in terms of different solute−solute hydrophilic interactions other than encapsulation while those in the postmicellar region are discussed in terms of the micellization process. The enthalpies of micellization are very large because of the complexed monomers contribution. ΔH (W → W + S) data for CR in DTAB micellar solutions were fitted through an equation previously reported which permits simultaneously obtaining the distribution constant of the uncomplexed CR and its enthalpy of transfer from the aqueous to the micellar phases. The equations were reviewed for CR in NaDS micellar solutions to account for the CR complexation and for the distribution of both the complexed and uncomplexed CR between the aqueous and the micellar phases. The derived properties are briefly discussed. The osmotic coefficient (ΦS) vs m S curve of both surfactants in W + CD shows a minimum at m S equal to the CD concentration (m CD) and a maximum at m S = m CD + cmc. These peculiarities are ascribed to the inclusion complex formation between the macrocyclic compound and the apolar chain of the surfactant. The addition of CR to water leads to the shift of the osmotic coefficient toward lower values. This shift is not very important for DTAB while it is for NaDS for which negative ΦS values were obtained. Sodium perfluorooctanoate behaves like NaDS. Since the osmotic coefficients for NaCl in W + CR are close to those in pure water, the results are interpreted in terms of complexed CR solubilization in the micellar phase.

Dairy-based functional beverages have been a growing segment as consumer demands for health foods have shifted focus from simply enhancing lifespan to protecting health. Green tea is often limited in use because of poor bioavailability and disagreeable taste. However, milk is considered an ideal platform for the delivery of active polyphenolic compounds in green tea. Furthermore, the antioxidant enzymatic activity and antioxidant index of polyphenols in green tea have been known to be protected through interaction with dairy proteins inside the unstable intestinal environment. In addition, consumption of green tea infused with milk has been found to have a significant impact on reducing skin wrinkles and roughness in elderly subjects, through a decrease in lipid peroxidation and a concomitant reduction in oxidative stress. A similar affinity has been observed between antioxidants in coffee and milk proteins. Dark chocolate has been known to contain significant phenolic content and antioxidant activity. The activation of protein complex NF-κB, which is responsible for cell survival, was found to be significantly reduced upon consumption of cocoa with water, whereas consuming cocoa with milk had no effect on the bioavailability of the phenolic compounds in cocoa. The popularity of dairy as the source for polyphenol fortified beverages in the diet will be dictated by optimization of the technology for maximizing the bioavailability of the antioxidants.