Abstract: In order to minimize the degradation of pinecone polyphenols in the stomach, pinecone polyphenols from Pinus koraiensis (PPH) were encapsulated by acidic polysaccharide fragments from Auricularia auricula (AAP) and polylysine (PLL) according to the principle of polyelectrolyte self-assembly, and response surface methodology was used to optimize the preparation process. The effect of AAP, PLL and PPH concentration as well as interaction between them on the encapsulation efficiency was evaluated. As a result, a quadratic polynomial model was established describing the process. Scanning electron microscopy (SEM) was used to investigate the morphology of the microparticles prepared under optimized conditions, and the release rate was studied in simulated gastrointestinal environment. The results showed that the fitness of the model was good. All of the three variables had significant effects on the response. The encapsulation efficiency of polyphenol microparticles were (86.57 ± 1.07)% and the drug loading was (24.03 ± 0.81)% at 900 μg/mL AAP, 30 μg/mL PLL and 110 μg/mL PPH concentration. The diameter of the microparticles was 200–500 nm. They were released slowly in simulated gastric environment but rapidly in simulated intestinal environment. The measured encapsulation efficiency matched with the predicted value, indicating that response surface methodology was a suitable method for optimizing the preparation of pinecone polyphenol microparticles. The degradation of pinecone polyphenol microparticles in the stomach environment was decreased relative to free pine polyphenols.

Key words: pinecone polyphenols, Auricularia auricula polysaccharide, self-assembly, microparticles, response surface methodology