Abstract:In order to improve the encapsulation rate and antimicrobial properties of sodium butyrate, sodium alginate/chitosan microcapsules of sodium butyrate were prepared by the complex coacervation method, and the key process parameters were optimized by response surface methodology. The appearance, morphology, structural features and antimicrobial properties of the optimized butyrate microcapsuleswere also analyzed. The results showed that the optimal formulation parameters of butyrate microcapsules with an embedding rate of 95.12% were sodium alginate 3.0%, chitosan 1.75%, sodium butyrate 2.5%, calcium chloride 3.0%, and embedding time 3 h. The obtained regression model was highly significant (P<0.000 1), with the lack of fit beingin significant (P=0.35), and the model fit being very good (R2=0.98). Scanning electron microscopy (SEM) showed that the sodium butyrate microcapsules were spindle-shaped with nodules. Fourier transform infrared spectroscopy (FT-IR) analysis showed that the characteristic peaks of sodium butyrate were all weakened or even disappeared, indicating that sodium alginate and chitosan formed microcapsules. The antibacterial rates of the sodium butyrate microcapsules against S. aureus and E. coli increased by 28.82% and 25.25%, respectively, compared with those of the sodium butyrate. After 24 h of intervention with sodium butyrate microcapsules (mass concentration: 2.0 g/L) against both bacteria, the total inhibition rate were higher than 99%. These results indicate that the sodium butyrate microcapsules prepared by the optimized process had a high embedding rate, compact and firm particles, and good antibacterial properties, which can provide a theoretical support for development of butyric acid-derived green antibiotic substitutes.
