Food-Grade Gelatin Nanoparticles: Preparation, Characterization, and Preliminary Application for Stabilizing Pickering Emulsions.

Xin Feng,Weijie Hu,Mi Tang,Hongjie Dai,Liang Ma,Tingwei Liu,Yuhao Zhang,Yuan Li,Yong Yu

doi:10.3390/foods8100479

Abstract

In this paper, the food-grade gelatin nanoparticles (GNPs) were prepared by a two-step desolvation method and using genipin as a cross-linker. The GNPs with narrow size distribution and good dispersion could be obtained only at pH 12. The effect of the genipin dosage (8–12 wt%) on the GNPs was systematically investigated. The results showed that the cross-linking degree of the GNPs increased with the increasing dosage of genipin, thus leading to a more obvious cross-linking morphology observed from scanning electron microscope (SEM). The obtained GNPs showed a good dispersibility with a size range of 386–438 nm. However, the GNPs cross-linked by 8 wt% genipin dosage revealed a relatively higher size because of the aggregation induced by hydrogen bond. The 10 wt% group had good thermal stability and storage stability. The optical microscopy results showed that the Pickering emulsions (30–50 vol% internal phase) stabilized by the GNPs had good uniformity and stability, even after 30 days of storage time, suggesting that the stable GNPs had great potential in food-grade Pickering emulsions.

Highlights

Emulsions are colloidal dispersions in which one immiscible liquid is dispersed in another immiscible liquid in the form of small droplets [1]
The gelatin nanoparticles (GNPs) prepared at pH 8–11 are not uniform, corresponding to their poor dispersion based on their polydispersity index (PDI) values (>0.3)
The results showed that GNPs with narrow size distribution and good dispersion only could be obtained at pH 12

Summary

Introduction

Emulsions are colloidal dispersions in which one immiscible liquid is dispersed in another immiscible liquid in the form of small droplets [1]. Further applications of the emulsions are limited because of poor stability and the use of surfactants. At this time, Pickering emulsions stabilized by the solid particles, with the advantages of no surfactants, high stabilities, and low cost, have garnered exponentially increasing interest in recent years [5,6]. The stability mechanism of Pickering emulsion is mainly because of the limited coalescence, bridging of droplets by a monolayer of particles, and the formation of gel network or greater steric hindrance to inhibit flocculation, coalescence or Ostwald ripening of the emulsion [7].

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