Encapsulation of α-tocopherol in whey protein isolate/chitosan particles using oil-in-water emulsion with optimal stability and bioaccessibility

Challenges and Advances in the Encapsulation of Bioactive Ingredients Using Whey Proteins

Functional foods represent an emerging trend in the food industry. Fortifying foods with bioactive ingredients results in health benefits and reduces the risk of disease. Encapsulation techniques protect sensitive ingredients from degradation due to heat, light, moisture and other factors. Among encapsulating materials, milk whey proteins are particularly attractive due to their availability, GRAS status and remarkable ligand-binding ability. Whey protein was once considered a by-product in the dairy industry but is now seen as a promising resource given its natural role as a nutrient carrier. This work reviews the encapsulation systems that employ whey proteins in the food industry. The structural features of β-lactoglobulin (β-LG), the main protein constituent of milk whey, are presented in the context of its ligand-binding properties. Different types of encapsulation systems using whey proteins are discussed, focusing on the recent advances in stable formulations of bioactives using whey protein, alone or in hybrid systems. Whey proteins are a valuable asset capable of binding sensitive bioactive compounds such as vitamins, polyphenols and antioxidants and forming stable complexes that can be formulated as nanoparticles, nanofibrils, emulsions and other micro- and nanostructures. Developing scalable, solid and stable encapsulation systems is identified as a main challenge in the field.

An Innovative Bio-Vehicle for Resveratrol and Tocopherol Based on Quinoa 11S Globulin-Nanocomplex Design and Characterization

Nanocomplexes, which possess immense potential to function as nanovehicles, can link diverse ligand compounds. The objective of the present study was to design and characterize resveratrol (RSV)- and tocopherol (TOC)-loaded 11S quinoa seed protein nanocomplexes. Firstly, molecular docking was performed to describe the probable binding sites between protein and ligands, and binding energies of -5.6 and -6.2 kcal/mol were found for RSV and TOC, respectively. Isothermal titration calorimetry allowed us to obtain the thermodynamic parameters that described the molecular interactions between RSV or TOC with the protein, finding the complexation process to be exothermic and spontaneous. 11S globulin intrinsic fluorescence spectra showed quenching effects exerted by RSV and TOC, demonstrating protein-bioactive compound interactions. The application of Stern-Volmer, Scatchard, and Förster resonance energy transfer models confirmed static quenching and allowed us to obtain parameters that described the 11S-RSV and 11S-TOC complexation processes. RSV has a higher tendency to bind 11S globulin according to ITC and fluorescence analysis. Secondly, the protein aggregation induced by bioactive compound interactions was confirmed by dynamic light scattering and atomic force microscopy, with diameters <150 nm detected by both techniques. Finally, it was found that the antioxidant capacity of a single 11S globulin did not decrease; meanwhile, it was additive for 11S-RSV. These nanocomplexes could constitute a real platform for the design of nutraceutical products.

Protection of α-Tocopherol from UV-Induced Degradation by Encapsulation into Zein Nanoparticles

Vitamin E is a fat-soluble vitamin with several forms. Among these, α-tocopherol (TOC) is preferentially absorbed and accumulated in humans. In the body, it acts as an antioxidant, helping to protect cells from the damage caused by free radicals. It is an organic chemical compound that undergoes degradation upon irradiation with UV light. To protect this bioactive chemical compound from UV light degradation, encapsulation was carried out using zein as a shell material. Due to the unique phase diagram of TOC in aqueous ethanol, the encapsulation efficiency was >99%. The size of encapsulated particles was ~300 nm or smaller, and the thickness of the shell wall was ~30 nm. The presented procedure offers the most simple and efficient encapsulation process that yields edible products. The investigation of the irradiation effect of UV on TOC revealed that the encapsulation effectively blocks UV light and prevents TOC from being degraded. The presented procedure offers an instantaneous and highly efficient encapsulation process, which yields edible products.

Improving physicochemical characteristics and cytotoxicity of baicalin esters by liposome encapsulation

The instability of ester bonds, low water solubility, and increased cytotoxicity of flavonoid glycoside esters significantly limit their application in the food industry. Therefore, the present study attempted to resolve these issues through liposome encapsulation. The results showed that baicalin butyl ester (BEC4) and octyl ester (BEC8) have higher encapsulation and loading efficiencies and lower leakage rate from liposomes than baicalin. FTIR results revealed the location of BEC4 and BEC8 in the hydrophobic layer of liposomes, which was different from baicalin. Additionally, liposome encapsulation improved the water solubility and stability of BEC4 and BEC8 in the digestive system and PBS but significantly reduced their cytotoxicity. Furthermore, the release rate of BEC4 and BEC8 from liposomes was lower than that of baicalin during gastrointestinal digestion. These results indicate that liposome encapsulation alleviated the negative effects of fatty chain introduction into flavonoid glycosides.

The aggregation behavior between soybean whey protein and polysaccharides of diverse structures and their implications in soybean isoflavone delivery

The use of polysaccharides to recover soybean whey protein (SWP) from whey wastewater is recognized as an effective approach. However, the recovery rate can vary due to differences in the structure and compound ratios of the polysaccharides involved. The interaction between SWP and polysaccharides (sodium alginate, SA; chitosan, CHI; carrageenan, CAR) at different ratio was investigated. We harnessed these complexes to fabricate emulsions aimed at delivering soybean isoflavones. The results showed that the addition of polysaccharides unfolded the structure of SWP. The intermolecular hydrogen bonds within SWP-SA were stronger than those of the other complexes. These structural changes showed consistency across different ratios. The mean particle size of the complexes increased. SWP-SA exhibited the lowest interfacial tension. The emulsion with SWP-SA at 300 W demonstrated superior stability, and the bioavailability of soybean isoflavones increased by 3-6 %. These results shed light on the promising potential of polysaccharide-based strategies for SWP recovery and the effective delivery of soybean isoflavones.

Phycocyanin-chitosan complex stabilized emulsion: Preparation, characteristics, digestibility, and stability

Phycocyanin is a natural pigment protein with antioxidant, anti-tumor, and anti-inflammatory properties, but its relatively poor emulsibility limits its use in the food industry. In order to improve the emulsifying capacity of phycocyanin, a novel phycocyanin-chitosan complex was prepared, and the characteristics, digestibility, and stability of emulsion containing oil droplets stabilized by the complex were investigated. The results showed that the phycocyanin-chitosan complex had better stability and lower interfacial tension at pH 6.5 than phycocyanin, and it significantly improved the stability of emulsion and inhibited the aggregation of oil droplets. The phycocyanin-chitosan complex stabilized emulsion showed better physical stability, digestibility, and oxidation stability than the phycocyanin emulsion. The particle size of the phycocyanin-chitosan complex stabilized emulsion was very small (from 0.1 to 2 μm), and its absolute value of zeta potential was high. Overall, this study suggests that the phycocyanin-chitosan complex effectively improved the emulsifying capacity of phycocyanin.

Encapsulation and antibacterial studies of goji berry and garlic extract in the biodegradable chitosan

As known, the chitosan is a biodegradable biopolymer with antibacterial properties, therefore it is used in the fields of pharmacy, medical, wastewater treatment, biotechnology, cosmetics, textiles, and agriculture. Apart from these, the chitosan has an important place in the food industry with its widespread use. In this research article, the chitosan were encapsulated with the taurine and garlic extracts by the spray dryer. The CSA and CSB compounds synthesized as final products were analyzed by Fourier transformed infrared spectroscopy (FTIR) and High Performance Liquid Chromatography (HPLC). The effect of the encapsulation process on the molecular weight of the polymer structure was investigated using the cryoscopy method. The compound CSA represents 1/2 encapsulation of chitosan with taurine and increased garlic extracts, respectively, while CSB represents 1/1 encapsulation of chitosan with increased taurine and fixed garlic extracts. The % antioxidant activity of the final products was determined by DDPH method. The inhibition zone and surface activity proporties of the CSA and CSB were carried out against Listeria monocytogenes, Staphylococcus aureus, E. coli, and Salmonella bacteria. The results obtained as a result of the analyzes were evaluated, and optimum values were determined for use in food packaging.

Whey Protein Isolate-Mesona chinensis Polysaccharide Conjugate: Characterization and Its Applications in O/W Emulsions

Mesona chinensis polysaccharide (MCP), a common thickener, stabilizer and gelling agent in food and pharmaceuticals, also has antioxidant, immunomodulatory and hypoglycemic properties. Whey protein isolate (WPI)-MCP conjugate was prepared and used as a stabilizer for O/W emulsion in this study. FT-IR and surface hydrophobicity results showed there could exist interactions between -COO- in MCP and -NH³⁺ in WPI, and hydrogen bonding may be involved in the covalent binding process. The red-shifted peaks in the FT-IR spectra suggested the formation of WPI-MCP conjugate, and MCP may be bound to the hydrophobic area of WPI with decreasing surface hydrophobicity. According to chemical bond measurement, hydrophobic interaction, hydrogen bond and disulfide bond played the main role in the formation process of WPI-MCP conjugate. According to morphological analysis, the O/W emulsion formed by WPI-MCP had a larger size than the emulsion formed by WPI. The conjugation of MCP with WPI improved the apparent viscosity and gel structure of emulsions, which was concentration-dependent. The oxidative stability of the WPI-MCP emulsion was higher than that of the WPI emulsion. However, the protection effect of WPI-MCP emulsion on β-carotene still needs to be further improved.

Effect of Oil Type on Spatial Partition of Resveratrol in the Aqueous Phase, the Protein Interface and the Oil Phase of O/W Emulsions Stabilized by Whey Protein and Caseinate

Oil-in-water emulsions contain the inner oil phase, the protein membrane at the interface and the aqueous phase. In this study, the spatial partition of resveratrol was investigated in sunflower oil, fish oil, medium-chain triglyceride (MCT) and peppermint oil emulsions stabilized by native whey protein isolate (WPI), heat-denatured WPI and sodium caseinate. Resveratrol was added in the aqueous phase of emulsions and its partition was analyzed in term of resveratrol solubility in bulk oil and in the aqueous phase of protein, protein concentration and interfacial protein. The final concentrations of resveratrol in the aqueous phase were basically greater than those in the oil phase of fish oil, sunflower oil and MCT oil emulsions, while the final concentrations of resveratrol in the oil phase were greater than those in the aqueous phase of peppermint oil emulsions. The difference in the interfacial partition of resveratrol and proteins increased as the polyphenol solubility in bulk oil increased. Resveratrol solubility in the oil phase drove its transfer from the aqueous phase into the oil phase in all emulsions, except that the interfacial protein also contributed to the transfer in fish oil emulsions. The oil–water interface provided the microenvironment for the enrichment of resveratrol by proteins.

Whey Protein Isolate-Chitosan PolyElectrolyte Nanoparticles as a Drug Delivery System

Whey protein isolate (WPI), employed as a carrier for a wide range of bioactive substances, suffers from a lack of colloidal stability in physiological conditions. Herein, we developed innovative stabilized PolyElectrolyte Nanoparticles (PENs) obtained by two techniques: polyelectrolyte complexation of negatively charged WPI and positively charged chitosan (CS), and ionic gelation in the presence of polyanion tripolyphosphate (TPP). Therefore, the WPI-based core was coated with a CS-based shell and then stabilized by TPP at pH 8. The nanostructures were characterized by physiochemical methods, and their encapsulation efficiency and in vitro release were evaluated. The spherical NPs with an average size of 248.57 ± 5.00 nm and surface charge of +10.80 ± 0.43 mV demonstrated high encapsulation efficiency (92.79 ± 0.69) and sustained release of a positively charged chemotherapeutic agent such as doxorubicin (DOX). Z-average size and size distribution also presented negligible increases in size and aggregates during the three weeks. The results obtained confirm the effectiveness of the simultaneous application of these methods to improve the colloidal stability of PEN.

Fabrication and Characterization of Chitosan-Pea Protein Isolate Nanoparticles

Chitosan (CS) and pea protein isolate (PPI) were used as raw materials to prepare nanoparticles. The structures and functional properties of the nanoparticles with three ratios (1:1, 1:2 1:3, CS:PPI) were evaluated. The particle sizes of chitosan-pea protein isolate (CS-PPI) nanoparticles with the ratios of 1:1, 1:2, and 1:3 were 802.95 ± 71.94, 807.10 ± 86.22, and 767.75 ± 110.10 nm, respectively, and there were no significant differences. Through the analysis of turbidity, endogenous fluorescence spectroscopy and Fourier transform infrared spectroscopy, the interaction between CS and PPI was mainly caused by electrostatic mutual attraction and hydrogen bonding. In terms of interface properties, the contact angles of nanoparticles with the ratio of 1:1, 1:2, and 1:3 were 119.2°, 112.3°, and 107.0°, respectively. The emulsifying activity (EAI) of the nanoparticles was related to the proportion of protein. The nanoparticle with the ratio of 1:1 had the highest potential and the best thermal stability. From the observation of their morphology by transmission electron microscopy, it could be seen that the nanoparticles with a ratio of 1:3 were the closest to spherical. This study provides a theoretical basis for the design of CS-PPI nanoparticles and their applications in promoting emulsion stabilization and the delivery of active substances using emulsions.