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The utilization of oils in the food industry can be facilitated by converting into a powdered form using microencapsulation technologies. In this study, coatings formed from macadamia protein isolate (MPI) and chitosan hydrochloride (CHC) were assessed for their ability to facilitate the microencapsulation of macadamia oil by spray dried, and all encapsulation efficiency was higher than 87.0%. The physicochemical properties of macadamia oil powders were then characterized. In addition, changes in the particle size, aggregation state, and creaming stability of rehydrated emulsions were analyzed during storage. The addition of CHC significantly enhanced the water-solubility and wettability but decreased the flowability of microencapsulated oil. Powdered macadamia oil produced at MPI/CHC = 5:1 had the highest encapsulation efficiency (94.2%), best oxidation stability (<4 meq/kg), and best rehydration properties. Overall, MPI/CHC could be used as a good emulsifier for producing stable rehydrated emulsion, which may therefore be useful in certain food applications., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

BACKGROUND: Rutin is a natural bioactive flavonoid that is poor in water solubility and chemical stability. Encapsulation can be used to protect bioactive molecules from chemical or physical decomposition during food processing and storage. Thus, the effect of initial particle size on the ability of oil‐in‐water emulsions to retain rutin during storage was investigated. RESULTS: Rutin was encapsulated in oil‐in‐water emulsions with different mean surface‐weighted diameters: d3,2 = 0.56 μm (small), 0.73 μm (medium), and 2.32 μm (large). As expected, the resistance of the emulsions to coalescence and creaming during storage increased as the particle size decreased due to weakening of the colloidal and gravitational forces acting on the droplets. The concentration of rutin in the emulsions decreased during storage (28 days), which was mainly attributed to photodegradation of the flavonoid. The loss of rutin from the emulsions during storage was fitted using a second‐order equation. The rutin degradation rate constant k decreased and the half‐life t1/2 increased with decreasing droplet size, which was attributed to the stronger encapsulation and light scattering by smaller oil droplets reducing the amount of light that can penetrate into the emulsions. CONCLUSION: This study has important implications for the design of more efficacious emulsion‐based delivery systems for incorporating health‐promoting nutraceuticals into foods. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Protein–polyphenol interactions influence emulsifying properties in both directions. Puerarin (PUE) is an isoflavone that can promote the formation of heat-set gels with whey protein isolate (WPI) through hydrogen bonding. We examined whether PUE improves the emulsifying properties of WPI and the stabilities of the emulsions. We found that forming composites with PUE improves the emulsifying properties of WPI in a concentration-dependent manner. The optimal concentration is 0.5%, which is the highest PUE concentration that can be solubilized in water. The PUE not only decreased the droplet size of the emulsions, but also increased the surface charge by forming composites with the WPI. A 21 day storage test also showed that the maximum PUE concentration improved the emulsion stability the most. A PUE concentration of 0.5% improved the stability of the WPI emulsions against environmental stress, especially thermal treatment. Surface protein loads indicated more protein was adsorbed to the oil droplets, resulting in less interfacial WPI concentration due to an increase in specific surface areas. The use of PUE also decreased the interfacial tension of WPI at the oil–water interface. To conclude, PUE improves the emulsifying activity, storage, and environmental stability of WPI emulsions. This result might be related to the decreased interfacial tension of WPI–PUE composites. [ABSTRACT FROM AUTHOR]

It is challenging to incorporate lycopene, a strongly hydrophobic nutraceutical, into functional foods because of its low water-solubility and poor bioaccessibility. In this study, we therefore examined the potential of alginate-based emulsion gels to encapsulate and deliver lycopene. Alginate can be gelled using either internal or external gelation mechanisms, but few studies have compared the advantages and disadvantages of these two approaches for producing emulsion gels. For this reason, we compared the structure, water distribution, water mobility, and simulated digestion of lycopene-loaded emulsion gels formed by gelling alginate within the aqueous phase using either the internal or external methods. The internal gelation method produced emulsion gels that contained smaller oil droplets, and had a higher hardness, water holding capacity, and freeze-thaw stability. Moreover, the internal gelation method led to emulsion gels that had a slightly higher lycopene bioaccessibility (36.1%) than the ones formed by the external gelation method (33.4%). These findings are important for optimizing the design and fabrication of emulsion gels suitable as delivery systems for nutraceuticals in the food industry. [Display omitted] • Alginate-based emulsion gels prepared with internal and external gelation mechanisms. • Internal gelation mechanism led to a more uniform gel network structure. • Internal emulsion gels showed higher water holding capacity. • Internal emulsion gels enabled higher retention and bioaccessibility of lycopene. [ABSTRACT FROM AUTHOR]

In present study, the impact of rutin concentration and pretreatment (direct mixing versus pH-driven) of rutin-protein complexes to form and stabilize bilayer emulsions was examined. Bilayer emulsions prepared using the pH-driven method contained smaller oil droplets and had a higher resistance to aggregation and creaming than those prepared using the direct method. The concentration of whey protein isolate at the oil droplet surfaces decreased as the rutin concentration was increased. The oil-water interfacial tension decreased as the rutin concentration in the rutin-whey protein isolate complexes increased, reaching a value of 10.4 mN/m at 0.6 mg/mL rutin. Fluorescence spectroscopy suggested that rutin interacted with the whey protein isolate surfaces mainly through hydrophobic interactions. Moreover, there appeared to be more binding sites and stronger binding interactions when the pH-driven method was used to form the complexes, rather than the direct mixing method. This study suggests that rutin may be used to improve the functional performance of whey protein isolate as emulsifiers in bilayer emulsions. [Display omitted] • Rutin-whey protein isolate (WPI) complexes were prepared. • Rutin-WPI complexes improved the aggregation stability of bilayer emulsions. • Rutin-WPI complexes reduced the interfacial tension at the oil-water interface. • Rutin bound more strongly to whey protein using a pH-driven method. [ABSTRACT FROM AUTHOR]