This paper introduces advanced systems and technique in the field of colloidal dispersions. These systems include the double emulsions, the cubosomes and the solid lipid nanoparticles (SLNs) which are favored by their capacity in the controlled release of ingredients, colorants, drugs, minerals and antioxidant particles. Double emulsions (both water-in-oil-in-water W/OW and oil-in-water-in-oil O/W/O) are considering as ideal materials for microencapsulation while cubosome and SLNs are submicron colloidal carriers. The structure, formulation and applications of those systems will be provided. In the preparation of colloidal dispersions, membrane technology is an interesting alternative method because of low energy consumption and high efficiency. The principle and operation of membrane systems in microemulsification as well as their applications will be summarized and presented.

This article investigates the stability of oil – in water – in oil double emulsions (sunflower oil/water/palm oil) with various water concentrations (40-50-60%, w/w) in the presence of some biopolymers. Double emulsions were prepared using Ultra Turrax homogenizer followed by fast crystallization. The results of the study revealed the high stability of O/W/O double emulsions at 5 °C can be achieved by combining sodium caseinate (SC), k-carrageenan (KC) with soy lecithin. The appropriate time for cold homogenization is 15 minutes at the speed of 5000 rpm. Graphical Abstract

Peristrophe bivalvis (L.) Merr. (Acanthaceae) is a Vietnamese herb that is rich in anthocyanin, a natural colorant. However, the common extraction methods for this pigment often accompany with the presence of contaminated compounds. This study, therefore, focused on applying the aqueous two-phase system (ATPS), a green method for extracting and purifying anthocyanin in the leaf extract. The obtained results revealed that an ATPS composing from ethanol and ammonium sulfate with the concentrations of 32.5% and 25%, respectively, can recover 80% anthocyanin in leaf while eliminating 80% contaminated nitrogen compounds. Besides, the shelf-life of pigment in the purified extract was also elongated significantly in comparison with that in the crude extract. Graphical Abstract

Coffee pulp is an abundant residue from the coffee industry, but it still contains large amounts of valuable compounds such as polyphenols. The extraction of polyphenols from coffee pulp by the conventional method is accompanied by contaminated compounds. This study, therefore, applied an aqueous two-phase system consisting of different ratios of ethanol/ammonium sulfate to eliminate impurities from coffee-pulp crude extract. The purification efficiency was evaluated via total polyphenol content, antioxidant activity and two major polyphenols in coffee pulps including chlorogenic acid and caffeic acid. Results showed that phenolic compounds mostly predominated in the alcohol-rich phase in which the antioxidant activity was greatly increased after the purification process. Compared to un-purified crude-coffee extract, the antioxidant activity of the purified samples increased approximately 34%, which was assumed to occur due to the slight increase of chlorogenic acid and caffeic acid. Fourier-transform infrared spectroscopy supported the effectiveness of the purification process by eliminating some impurities.