Quercetagetin-loaded zein-propylene glycol alginate composite particles induced by calcium ions: Structural comparison between colloidal dispersions and lyophilized powders after in vitro simulated gastraintestinal digestion

- Qucertagetin (Q) was encapsulated in zein-propylene glycol alginate (PGA) composites.
- Erosion and degradation of Q-loaded Zein-PGA composite particles were investigated.
- The combination of zein and PGA by calcium ions led to the controlled release of Q.
- Morphological difference between dispersion and powder appeared in gastric fluids.

Zein-propylene glycol alginate (PGA) composite particles induced by calcium ions (Ca2+) in the form of both liquid and solid were designed as the vehicle of qucertagetin (Q). Erosion and degradation were investigated to predict potential micro-structural changes and release property of Q after in vitro digestion. Results showed that the combination of zein with PGA in the presence of Ca2+ further reduced the degradation of particles. After digestion in simulated intestinal fluids (SIF), the release amount (22.0%) of Q in Zein-PGA composite dispersions with Ca2+ was lower than that of 52.8% in zein alone. The morphological difference between liquid and solid samples occurred in the digestion stage of SGF. Digestion of zein colloidal dispersions in SGF resulted in microsphere disintegration and plate-like structure appeared. A diamond-like pattern was presented after digestion of Zein-PGA composite colloidal dispersions, while a fine filamentous network structure filled with small particles appeared in lyophilized particles.

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