Encapsulation of grape seed oil in oil-in-water emulsion using multilayer technology: Investigation of physical stability, physicochemical and oxidative properties of emulsions under the influence of the number of layers.

Many studies have shown that grape seed oil (GSO) is one of the vegetable fats that are plentiful in essential fatty acids and can be used as a fat substitute or to modify fat in food products to reduce saturated fatty acids. However, due to its low solubility and high sensitivity to oxidation, it is necessary to develop delivery systems that can distribute GSO in food more effectively. Recently, the preparation of emulsions using the layer-by-layer (LBL) method has many advantages in delivering lipid-soluble functional compounds. This research was used to check the formation of GSO oil-loaded primary, secondary and tertiary multilayer emulsions stabilized by mixture of anionic gelatin, cationic chitosan, and anionic basil seed gum (BSG) as the aqueous phase at pH 5, prepared using a layer-by-layer electrostatic deposition technique. Multilayer emulsions prepared by GSO and a mixture of gelatin, chitosan, and BSG as the aqueous phase at pH 5. Finally, the effect of the number of layers on the physicochemical properties (particle size, viscosity, turbidity, refractive index, and physical stability) and oxidative stability (peroxide value, thiobarbituric acid value, and fatty acid profile) during the storage time (30 days) at two temperatures 25 °C & 4 °C was investigated. Also, the zeta potential and Fourier transform infrared spectroscopy (FTIR) of mono-layer and multi-layer emulsions were investigated. The results revealed that by increasing the number of layers of multi-layer emulsion of GSO, the stability has improved. Thus, the tertiary emulsion has been more effective than the other two emulsions in maintaining the physicochemical characteristics and stability over time (P < 0.001). Morphological characterization and FTIR spectroscopy results confirmed that gelatin, chitosan, and BSG were successfully loaded into the LBL emulsions. This study can improve the original percept of multilayer emulsions and promulgate their potential applications for the entire encapsulation of essential fatty acids to enrich and prevent peroxide attack.

Effects of novel and conventional thermal treatments on the physicochemical properties of iron-loaded double emulsions.

In this work, changes in different physicochemical properties of iron-loaded double emulsions (DEs) were monitored under the influence of novel (microwave and ohmic) and conventional heat treatments. Microwave heating led to destabilization and obvious phase separation. As compared to control samples, heat treatment increased particle size, light absorbance, centrifugal instability, iron expulsion from the internal aqueous phase, color difference, chemical instability of the lipid phase, release of iron in simulated gastrointestinal fluids and iron bioavailability in cell line SW742. Emulsion viscosity and whiteness index decreased after heat treatment, whereas the zeta-potential remained unchanged. There was a negative correlation between physicochemical stability and heat treatment intensity. Conventional heating resulted in greater stability than ohmic heating. Yoghurt samples (as model systems) were fortified with either iron-loaded or iron-free DEs. Our results showed that the presence of iron in the aqueous phase resulted in significant lipid oxidation during storage.

Physicochemical properties of fish oil in water multilayer emulsions prepared by a mixture of whey protein isolate and water-soluble fraction of Farsi gum.

Physicochemical properties and storage stability of fish oil (FO) in water multilayer emulsions, stabilized with different mixtures of whey protein isolate (WPI) and water-soluble fraction of Farsi gum (WSFG), were studied under the effects of total biopolymer concentration (TBC), WSFG:WPI mixing ratio (MR) and pH for 1 month. pH reduction decreased the surface potential of dispersed droplets; however, an increase in the WSFG:WPI MR (at constant pH values corresponding to electrostatic interactions) significantly increased the absolute values of surface potential and hence the physical stability of emulsions. An increase in TBC increased droplet size and emulsion viscosity. The emulsion viscosity was also positively correlated with WSFG:WPI MR. During storage, higher values of TBC and WSFG:WPI MRs led to lower absorbance values. An increase in the WSFG:WPI MR and TBC significantly retarded the oxidation of emulsified FO.

Polysaccharide type and concentration affect nanocomplex formation in associative mixture with ß-lactoglobulin.

The main objective of this work was to investigate the effects of polysaccharide type (gum Arabic, GA and/or carboxymethyl cellulose, CMC) and concentration (0-0.2% (w/w)) on the electrostatic interactions with ß-lactoglobulin (BLG). Biopolymer interaction was studied using turbidimetric analysis, dynamic light scattering (DLS), electrophoretic mobility and relative viscosity measurements. Complexes were developed at pH values below the isoelectric point (pI) of BLG. Increasing polysaccharide concentration increased the stability of nanocomplexes through increasing the negative charges carried by complexes. The differences between GA and CMC were attributed to the polysaccharide structure (linear or branched chains), charge density and flexibility. Phase contrast optical microscopy showed that complexation was of nucleation and growth type mechanism. Relative viscosity measurements confirmed that wrapping phenomenon occurred in both associative mixtures.