Purification of Four Caffeoylquinic Acid Derivatives from the Flowers of Gynura Procumbens by HSCCC.

Four caffeoylquinic acid derivatives from the Gunura procumbens flowers (GPF) were successfully isolated and purified by high-speed counter-current chromatography (HSCCC). Ethyl acetate-methanol-water (3:1:3, v/v/v) was the optimum biphasic solvent system, which was selected by high-performance liquid chromatography (HPLC) and run on a preparative scale where the lower aqueous phase was used as the mobile phase with a head-to-tail elution mode. Chlorogenic acid (3.83 mg), Isochlorogenic acid A (6.51 mg), Isochlorogenic acid B (4.38 mg) and Isochlorogenic acid C (4.47 mg) were obtained for the first time in an one-step HSCCC separation from 800 mg of the crude extracts. The purities of four compounds were determined to be >95% by HPLC. Chemical structures of each isolated compounds were identified by nuclear magnetic resonance and electrospray ionization mass spectrometry methods. It is worth noting that all the four compounds were isolated here for the first time from GPF and this work confirms the effectiveness of HSCCC for the separation of compounds contained in complex samples, and provides a foundation for further exploitation of G. procumbens.

Development of antioxidant Pickering high internal phase emulsions (HIPEs) stabilized by protein/polysaccharide hybrid particles as potential alternative for PHOs.

We report for the first time the usage of mono-dispersed gliadin/chitosan hybrid particles as a particulate emulsifier for Pickering high internal phase emulsions (HIPEs) development. The hybrid particles with partial wettability were fabricated at pH 5.0 using a facile anti-solvent route. Stable Pickering HIPEs with internal phases of up to 83% can be prepared with low particle concentrations (0.5-2%). The hybrid latexes were effectively adsorbed and anchored at the oil-water interface to exert steric hindrance against coalescence. Concomitantly, the compressed droplets in Pickering HIPEs to form a percolating 3D-network framework endowed the emulsions viscoelastic and self-standing features. The protective effect of Pickering HIPEs on curcumin was confirmed, and the content of primary oxidation products in HIPEs was slightly lower than that in bulk oil. This work opens an attractive strategy to convert liquid oils to viscoelastic soft solids without artificial trans fats, as a potential alternative for PHOs.

Fabrication and characterization of Pickering emulsions and oil gels stabilized by highly charged zein/chitosan complex particles (ZCCPs).

Herein, we reported a facile method to fabricate ultra-stable, surfactant- and antimicrobial-free Pickering emulsions by designing and modulating emulsions' interfaces via zein/chitosan colloid particles (ZCCPs). Highly charged ZCCPs with neutral wettability were produced by a facile anti-solvent procedure. The ZCCPs were shown to be effective Pickering emulsifiers because the emulsions formed were highly resistant to coalescence over a 9-month storage period. The ZCCPs were adsorbed irreversibly at the interface during emulsification, forming a hybrid network framework in which zein particles were embedded within the chitosan network, yielding ultra-stable food-grade zein/chitosan colloid particles stabilized Pickering emulsions (ZCCPEs). Moreover, stable surfactant-free oil gels were obtained by a one-step freeze-drying process of the precursor ZCCPEs. This distinctive interfacial architecture accounted for the favourable physical performance, and potentially oxidative and microbial stability of the emulsions and/or oil gels. This work opens up a promising route via a food-grade Pickering emulsion-template approach to transform liquid oil into solid-like fats with zero trans-fat formation.

Wettability, surface microstructure and mechanical properties of films based on phosphorus oxychloride-treated zein.

BACKGROUND: Zein, the predominant protein in corn, has been extensively studied as an alternative packaging material in edible and biodegradable films. However, films made from 100% zein are brittle under normal conditions. The aim of this investigation was to improve the film-forming properties of zein by chemical phosphorylation. The surface hydrophobicity, surface microstructure and mechanical properties of films based on untreated and phosphorus oxychloride (POCl(3))-treated zein were evaluated and compared. The effect of POCl(3) treatment on the rheological properties of zein solutions was also studied. RESULTS: POCl(3) treatment, especially at pH 7 and 9, led to an increase in the apparent viscosity of zein solutions. Atomic force microscopy (AFM) analysis showed that the film based on POCl(3) -treated zein at pH 7 had a stone-like surface microstructure with a higher roughness (R(q)) than the untreated zein film. The AFM data may partially account for the phenomenon that this film exhibited high surface hydrophobicity (H(0) ). POCl(3) treatment diminished the tensile strength (TS) of zein films from 4.83-6.67 to 1.3-2.29 MPa. However, the elongation at break (EAB) of the films at pH 7 and 9 increased from 3.0-4.5% (control film) to 150.1-122.7% (POCl(3) -treated film), indicating the potential application of zein films in wrapping foods or in non-food industries such as sugar, fruit or troche that need good extension packing materials. CONCLUSION: The data presented suggest that the properties of zein films could be modulated by chemical phosphorylation treatment with POCl(3) at an appropriate pH value.