RESUMO
In this study, the enhancement of Pickering effect of ovalbumin (OVA) with bacterial cellulose nanofibers (BCNFs) prepared by electron beam irradiation was investigated and the environmental stability of oil-in-water Pickering emulsions stabilized by OVA/BCNFs complexes was explored by varying ratios of OVA/BCNFS (1:0.2, 1:0.4, 1:0.6, 1:0.8, 1:1) and oil phase concentrations (10 %, 20 %, 30 %, 40 %, 50 %, 60 %). Droplet sizes of Pickering emulsions were decreased with the increase of the proportion of BCNFs, while the viscosity and storage modulus (G') of Pickering emulsions were increased. The gel strength of Pickering emulsions was positively correlated with the oil phase content. Pickering emulsions stabilized by OVA/BCNFs complexes were endowed excellent environmental stability under varying pH, ionic strength, and thermal conditions. Moreover, after encapsulating curcumin in Pickering emulsions, the retention rates of curcumin were improved significantly during room temperature, UV light, and thermal treatment. The present study would contribute to the advancement of novel protein/polysaccharide stabilizers and offer novel insight for investigating the stability of Pickering emulsions and delivering lipophilic bioactive compounds.
RESUMO
In this study, high internal phase Pickering emulsions (HIPPEs) were stabilized by the complexes of peanut protein isolate (PPI) and cellulose nanocrystals (CNCs) for encapsulation ß-carotene to retard its degradation during processing and storage. CNCs were prepared by H2SO4 hydrolysis (HCNCs), APS oxidation (ACNCs) and TEMPO oxidation (TCNCs), exhibiting needle-like or rod-like structures with nanoscale size and uniformly distributed around the spherical PPI particle, which enhanced the emulsifying capability of PPI. Results of optical micrographs and droplet size measurement showed that Pickering emulsions stabilized by PPI/ACNCs complexes exhibited the most excellent stability after 30 days of storage, which indicated that ACNCs had the most obvious effect to improve emulsifying capability of PPI. HIPPEs encapsulated ß-carotene (ßc-HIPPEs) were stabilized by PPI/ACNCs complexes and showed excellent inverted storage stability. Moreover, ßc-HIPPEs exhibited typical shear thinning behavior investigated by rheological properties analysis. During thermal treatment, ultraviolet radiation and oxidation, the retentions of ß-carotene encapsulated in HIPPEs were improved significantly. This research holds promise in expanding Pickering emulsions stabilized by proteins-polysaccharide particles to delivery systems for hydrophobic bioactive compounds.