In this study, pepper seed oil (PSO) was microencapsulated by spray drying at optimum conditions: oil/total solid material at 20% (w/w), gum Arabic/maltodextrin (GA/MD) at 1/5 (w/w), and air inlet temperature of 184 °C. Particle size distribution and morphology of the PSO powder (PSOP) were determined by a laser particle diameter analyzer and scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) were employed to identify the specific chemical groups of PSO, MD, and GA in the PSO-GA/MD complexes. The thermal stability of PSOP was evaluated by thermogravimetric (TGA) and differential thermal analysis (DTA). PSOP displayed inhibitory activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis although PSO had an antimicrobial activity against only Staphylococcus aureus. GA/MD microencapsulation resulted in significant preservation of PSO against oxidation during storage period.
Keywords: Antimicrobial activity; FTIR; Microencapsulation; NMR; Oxidation stability; Pepper seed oil; Thermal stability.
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