Development of whey protein isolate-phytosterols complexes stabilized oil-in-water emulsion for ß-carotene protection and delivery.

Although ß-carotene (BC) exerts beneficial effects on human health, the direct use of this compound as a nutritional supplement is hindered by its low water solubility and oxidation stability. Herein, we develop an oil-in-water emulsion stabilized by whey protein isolate (WPI)-phytosterols (PS) complexes as a delivery system for BC to overcome the above limitations. The rheology and stability of the emulsion were characterized, and the influence of the emulsion on the chemical stability and bioaccessibility of BC was discussed. The results showed that the PSs promoted the adsorption of WPI at the oil-water interface and improved the viscosity and viscoelasticity of the emulsion. The emulsion with a WPI:PS mass ratio of 25:2 (EWPI-PS) featured the highest fraction of interfacial adsorbed protein (88.73 %), excellent stability during 21-day storage at 25 °C. The BC retention rate of EWPI-PS (61.48 %) was significantly higher than that of the emulsion stabilized by WPI only (EWPI, 31.90 %) after 21-day storage at 50 °C. In addition, BC-loaded EWPI-PS showed higher freeze-thaw and thermal stability than BC-loaded EWPI, and a lower free fatty acid release rate and BC bioaccessibility than BC-loaded EWPI in simulated gastrointestinal digestion experiments. These results provide a theoretical basis for the WPI-PS complexes-stabilized emulsion as BC delivery system.

Whey protein isolate-phytosterols nanoparticles: Preparation, characterization, and stabilized food-grade pickering emulsions.

The preparation of whey protein isolate (WPI) particles by heat induction usually reduces both protein nutritional value and functionality. In this study, WPI and phytosterols (PSs) were used to prepare whey protein isolate-phytosterol (WPS) nanoparticles as stabilizers of oil-in-water Pickering emulsions, and the effects of PSs on the structure and function of the nanoparticles were studied. The results showed that the WPI and PSs combine through non-covalent bonding, which alters the nanoparticle structure and function. When the WPI/PSs mass ratio was 25:2, the nanoparticles (WPS-4) exhibited excellent interfacial wettability, emulsification stability, and antioxidant activity. The nanoparticles formed thick and dense interfacial films on the droplet surfaces to protect them, and the emulsion stabilized with the WPS-4 nanoparticles exhibited the best storage stability and oxidation stability. The emulsion can also reduce the digestion of lipids. These results provide a theoretical basis for the application of WPS nanoparticles.

Effects of inducer type and concentration on the formation mechanism of W/O/W double emulsion gels.

Insulin (INS, hydrophilic) and quercetin (Q, hydrophobic) have broad biological benefits; however, their application is limited because of their instability and poor bioaccessibility. Thus, in this study, water-in-oil-in-water (W/O/W) double emulsion gels based on black bean protein-sodium alginate Maillard conjugate-stabilized double emulsions were fabricated using three different inducers. The water holding capacity (WHC), intermolecular interaction forces, INS and Q encapsulation efficiencies (EEs), rheological and textural properties, microstructures, and structures were influenced by both inducer type [CaCl2, glucolactone (GDL), and glutamine transaminase (TGase)] and concentration. The addition of each inducer significantly increased the WHC, INS, and Q EEs, and textural properties of the emulsion gel. Moreover, the rheological behavior analysis showed that all the emulsion gels exhibited marked elastic behavior. These results will help develop an emulsion gel functional carrier based on a black soybean protein-carbohydrate-stabilized W/O/W double emulsion for the targeted and sustained release of drugs.

Co-delivery of insulin and quercetin in W/O/W double emulsions stabilized by different hydrophilic emulsifiers.

Insulin (hydrophilic) and quercetin (hydrophobic) have broad biological benefits; however, their rapid hydrolysis (via protease degradation) during digestion hinders their stability and delivery for absorption before degrading. In this study, we encapsulated insulin and quercetin using a self-assembled water-in-oil-in-water (W/O/W) double emulsion. We prepared the co-delivery emulsion by two-step emulsification and investigated the effects of the type of hydrophilic emulsifier for the outer water phase on the physicochemical properties, stability, and digestive properties. The black-bean-protein-stabilized W/O/W double emulsion had a higher absolute zeta potential value (52.80 mV), higher encapsulation efficiency (insulin: 95.7%, quercetin: 93.4%), lower viscosity, better emulsifying properties (EAI: 122.26 m2/g, ESI: 224 min), and lower levels of hydroperoxides (0.86 mmol/L) and TBARS (25.80 µmol/L) than emulsions stabilized by other hydrophilic emulsifiers. The emulsion yielded a 2.60- and 4.56-fold increase in the bioaccessibility of insulin and quercetin, respectively, while increasing their chemical stability and solubility under simulated gastrointestinal conditions.

Effect of carbohydrate type on the structural and functional properties of Maillard-reacted black bean protein.

Protein from black beans (Phaseolus vulgaris L.) has good solubility, emulsification, and antioxidant properties, with significant potential applications in the food industry. Maillard-reaction-mediated dry-heat glycosylation is a relatively safe modification method to improve the functional properties of black bean protein (BBP). Here, Maillard-reacted conjugates were prepared by applying 24-h dry-heating to induce a reaction between BBP and one of three carbohydrates (dextran, chitosan, and sodium alginate) at 70°C and 79% relative humidity. The resulting Maillard conjugates were designated as BBP-Dex, BBP-Ch, and BBP-SA, respectively. The formation of each Maillard conjugate was characterized by analyzing the grafting degree, free sulfhydryl (SH) groups content, and surface hydrophobicity, as well as the results of Fourier-transform infrared (FTIR) spectroscopy and fluorescence spectroscopy. The FTIR and fluorescence spectroscopy results provided information on the formation of the Maillard conjugates. The BBP-SA conjugate had a higher grafting degree and SH group content than the other two conjugates. The solubility, emulsifying properties, and antioxidant properties of the BBP were significantly improved after the Maillard reaction (p < 0.05). Moreover, the physicochemical and functional properties of the conjugates were superior to those of the BBP-carbohydrate mixtures, indicating that covalent interactions may be stronger than noncovalent interactions. This study provides theoretical guidance for future research on protein-carbohydrate conjugates. PRACTICAL APPLICATION: This study has great potential applications in the development of new multi-functional food ingredients and the realization of functional factor homeostasis, and provides scientific and theoretical bases for the application of protein-carbohydrate conjugate in the field of functional food.

The Synthesis of Backbone Thermo and pH Responsive Hyperbranched Poly(Bis(N,N-Propyl Acryl Amide))s by RAFT.

Hyperbranched poly(methylene-bis-acrylamide), poly(bis(N,N-propyl acryl amide)) (HPNPAM) and poly(bis(N,N-butyl acryl amide)) were synthesized by reversible addition-fragmentation chain transfer polymerization. HPNPAMs showed lower critical solution temperature (LCST) due to an appropriate ratio between hydrophilic and hydrophobic groups. The effects of reaction conditions on polymerization were investigated in detail. The structure of HPNPAM was characterized by ¹H NMR, FT-IR, Muti detector-size exclusion chromatography (MDSEC) and Ultravioletvisble (UV-Vis). The α value reached 0.20 and DB was 90%, indicating HPNPAMs with compact topology structure were successfully prepared. LCSTs were tuned by Mw and the pH value of the solution. The change of molecular size was assayed by dynamic light scattering and scanning electron microscope. These results indicated that the stable uniform nanomicelles were destroyed and macromolecules aggregated together, forming large particles as temperature exceeded LCST. In addition, after the cells were incubated for 24 h, the cell viability reached 80%, which confirmed this new dual responsive HPNPAM had low cytotoxicity.