Mannose-based surfactant as biofunctional nanoemulsion stabilizer.

The development and implementation of new amphiphiles based on natural resources rather than petrochemical precursors is an essential requirement due to their feedstock depletion and adverse environmental impacts. In addition, the use of bio-based surfactants can provide unique characteristics and improve the properties and versatility of the colloidal systems in which they are applied, such as emulsions. Here, the emulsification properties of a synthesized biocompatible mannose-based surfactant were investigated. Its behavior was evaluated in the presence of four different natural oils (castor, sunflower, olive and soybean) as well as two different aqueous phases (pure water and phosphate-buffered saline). The results highlighted its interest as surfactant in O/W nanoemulsions for all tested oil and aqueous phases, using a low-energy preparation protocol and relatively low surfactant concentrations. Furthermore, the mannose groups present on the polar head of the surfactant and adsorbed on the surface of the emulsion droplets were shown to retain their native biological properties. The specific mannose-concanavalin A binding was observed in vitro by the designed nanoemulsions, revealing the biorecognition properties of the surfactant and its potential applicability as a nanocarrier.

Design and Self-Assembly of Sugar-Based Amphiphiles: Spherical to Cylindrical Micelles.

Sugar-based amphiphiles are a relevant natural alternative to synthetic ones due to their biodegradable properties. An understanding of their structure-assembly relationship is needed to allow the concrete synthesis of suitable derivatives. Here, four different mannose-derivative surfactants are characterized by pendant drop, dynamic light scattering, small-angle X-ray scattering, cryotransmission electron microscopy, and molecular dynamics techniques in aqueous media. Measurements denote how the polysaccharide average degree of polymerization (DP¯) and the addition of a hydroxyl group to the hydrophobic tail, and thus the presence of a second hydrophilic moiety, affect their self-assembly. A variation in the DP¯ of the amphiphile has no effect in the critical micelle concentration in contrast to a change in the hydrophobic molecular region. Moreover, high-DP¯ amphiphiles self-assemble into spherical micelles irrespective of the hydroxyl group presence. Low-DP¯ amphiphiles with only one hydrophilic moiety form cylindrical micelles, while the addition of a hydroxyl group to the tail leads to a spherical shape.

Evaluation of the Preservation and Digestion of Seal Meat Processed with Heating and Antioxidant Seal Meat Hydrolysates.

Seal meat is of high nutritive value but is not highly exploited for human food due to ethical issues, undesirable flavors, and loss of nutrients during the processing/cooking step. In this work, commercially available processed seal meat was treated with its hydrolysates as preservatives with the aim of improving nutrient bioavailability. The contents of the nutrients were analyzed after digestion using a simulated dynamic digestion model, and the effects of different processing conditions, i.e., low-temperature processing and storage (25 °C) and high-temperature cooking (100 °C), of seal meat were investigated. Hydrolysates with antioxidant activity decreased the amounts of the less desirable Fe3+ ions in the seal meat digests. After treatment with hydrolysates at room temperature, a much higher total Fe content of 781.99 mg/kg was observed compared to other treatment conditions. The release of amino acids increased with temperature and was 520.54 mg/g for the hydrolysate-treated sample versus 413.12 mg/g for the control seal meat sample treated in buffer. Overall, this study provides useful data on the potential use of seal meat as a food product with high nutritive value and seal meat hydrolysates with antioxidant activity as preservatives to control oxidation in food.