Search

A novel nanoparticle (NP) delivery system was designed for encapsulation of bioactive compounds for which quercetin was used as a model. A combination of almond gum (AG) and shellac as biopolymers using the antisolvent method was employed to fabricate the NPs. The influence of several significant preparation factors was investigated. Bare shellac particles showed extreme aggregation when exposed to pH 1.2 (gastric acid conditions), whereas the colloidal system containing 0.7% AG was capable to form NPs with particle size of 197nm with no sign of physio-chemical instability at pH 1.2 and with an encapsulation efficiency (EE) of 78%. Addition of small amounts of polysorbate 80 and Quillaja Saponin led to a drastic decrease in particle size to 90 and 116nm, respectively, with an encapsulation efficiency higher than 98%. The morphology characterization of the NPs with Cryo-SEM revealed that most NPs were spherical with rough surfaces, indicating that AG adsorbed onto the shellac surface as was also reflected by electrokineic measurements. DSC and FTIR analyses indicated that inclusion of quercetin within the NPs coincided with a transition from the crystalline to the amorphous state. To conclude, this study presented the formulation of promising nanocarriers applicable not only in the food but also in the pharmaceutical industry.

Consumer demands for natural and clean label ingredients is promoting food and beverage manufacturers to replace synthetic emulsifiers with natural alternatives. This study examined the potential use of quillaja saponin (Q-Naturale 200®) as a natural emulsifier in model coffee creamers. The model liquid creamer was an oil-in-water emulsion (2% quillaja saponin, 10% medium chain triglycerides) that had a whitish milk color (lightness, L* = 86–90) similar to a commercial liquid creamer (L* = 91–93). The model creamer was stable to droplet aggregation and creaming from pH 3.5 to 7.0, which was attributed to the small droplet diameter (d

The susceptibility of omega-3 fatty acids to oxidation in foods can often be retarded using well-designed colloidal delivery systems. In this study, the ability of a natural antioxidant (casein) to inhibit the oxidation of flaxseed oil in oil-in-water nanoemulsions and filled hydrogel beads (microgels) was investigated. Nanoemulsions (D 43 = 0.31 μm) were fabricated by high-pressure homogenization using a quillaja saponin extract (Q-Naturale) as an emulsifier, whereas filled microgels (D 43 = 970 μm) were fabricated by injecting a 0.8% alginate solution containing nanoemulsions into a calcium solution using an extrusion device. The size of the particles in these colloidal delivery systems exhibited no major changes during 14-days storage at 55 °C. The oxidative stability of flaxseed oil droplets was better when they were encapsulated in microgels than when they were free, which was attributed to the greater surface area of exposed lipid in the latter case. The oxidative stability of both nanoemulsions and filled microgels was improved by adding caseinate as an antioxidant. Simultaneous incorporation of both caseinate and lipid droplets within microgels proved to be the most effective means of inhibiting lipid oxidation. Overall, these results provide valuable information for the development of colloidal delivery systems to encapsulate and protect omega-3 fatty acids for functional food applications.

The aim of this study was to investigate the possibility of stabilising foam bubbles in water by adsorption of calcium carbonate (CaCO3) particles. Because CaCO3 is hydrophilic and not surface-active, particles were hydrophobised in situ with several emulsifiers. The used emulsifiers were food-grade and negatively charged at the pH employed. The effect of particle addition on foamability and foam stability of solutions containing either β-lactoglobulin, sodium caseinate, Quillaja, sodium dodecanoate (SD) or sodium stearoyl-2-lactylate (SSL) was studied. It was found that the ability of the emulsifiers to induce surface activity such that the particles are able to adsorb to the air-water interface is related to their structure. The structure needs to consist of a well-defined hydrophobic part and a charged part. Large emulsifiers with a complex structure, such as β-lactoglobulin, sodium caseinate and Quillaja, were able to partially hydrophobise the particles but were not able to act synergistically with the particles to increase the foam stability. Low molecular weight emulsifiers, however, consisting of a single tail with one charged group, such as SD and SSL, adsorbed at the particle surface rendering the particles partially hydrophobic such that they adsorb to the air-water interface. In a subsequent investigation, the pH was changed to a value typical for food products (pH 6–7) and the addition of milk salts on the foamability and foam stability was assessed. Based on these results, the use of food-grade CaCO3 particles hydrophobised in situ with food-grade surfactants (SD or SSL) to prepare ultra-stable aqueous foams is demonstrated.

Nanoemulsions are utilized within the food, pharmaceutical, and personal care industries because of their unique physicochemical properties and functional attributes: high optical clarity; prolonged stability; and, enhanced bioavailability. For many applications, it is desirable to utilize natural ingredients to formulate nanoemulsions so as to create “label-friendly” products. In this study, we compared the effectiveness of a number of natural emulsifiers at fabricating corn oil-in-water nanoemulsions using dual-channel microfluidization. These emulsifiers were either amphiphilic biopolymers (whey protein and gum arabic) or biosurfactants (quillaja saponin and soy lecithin). Differences in the surface activities of these emulsifiers were characterized using interfacial tension measurements. The influence of emulsifier type, concentration, and homogenization pressure on the efficiency of nanoemulsion formation was examined. The long-term stability of the fabricated nanoemulsions was also monitored during storage at ambient temperature. For all of the natural emulsifiers, nanoemulsions could be produced by dual-channel microfluidization, with the mean particle diameter decreasing with increasing emulsifier concentration and homogenization pressure. Whey protein isolate and quillaja saponin were more effective at forming nanoemulsions containing fine droplets than gum arabic and soy lecithin, with a lower amount of emulsifier required and smaller droplets being produced. This effect was attributed to faster emulsifier adsorption and a greater reduction in interfacial tension leading to more efficient droplet disruption within the homogenizer for saponins and whey proteins. This study highlights the potential of dual-channel microfluidization for efficiently producing label-friendly nanoemulsions from natural emulsifiers.

The short- and mid-term adsorption kinetics of Quillaja Bark Saponin (QBS) biosurfactant at water–air interface was studied using a maximum bubble pressure and drop shape analysis techniques, respectively. The low values of diffusion coefficients at initial and close-to equilibrium stages of adsorption suggest that adsorption of QBS is mixed-diffusion barrier controlled. Increasing the ionic strength or decreasing pH helps to screen the negative charge of the glucuronic acid moiety of QBS and results in enhanced surface activity of QBS. The surface tension isotherms at pH 2.6 (HCl solution, unbuffered), 6.2 (pure water, unbuffered) and 7.4 (phosphate buffer, I = 0.1 M) were fitted using the Frumkin model. The influence of a model protein (hen egg lysozyme, LYS) on adsorption of QBS on short- and mid-term timescales was studied at fixed LYS concentration of 10 −5 M and varying QBS concentration. The synergistic effects in QBS adsorption were observed due to formation of LYS–QBS complex, whose surface activity increases at low QBS concentrations. The complex may be formed either in bulk solution, prior to adsorption, or directly at the surface, through co-adsorption of the slower diffusing component on the pre-adsorbed layer of the other component. At high concentrations of QBS, the latter dominates the adsorption process, depleting the surface from LYS and LYS–QBS complex. The synergistic effects found in adsorption kinetics of LYS–QBS mixtures were assessed in foamability tests using a modified Bikerman method.