The Antibacterial Activity and Pickering Emulsion Stabilizing Effect of a Novel Peptide, SA6, Isolated from Salt-Fermented Penaeus vannamei

This study aimed to improve bacterial inhibition in Pickering emulsions during storage using antimicrobial peptides. A peptide (ARHQGVMVGMGQK), designated SA6, isolated from the broth of salt-fermented shrimp (Penaeus vannamei). Peptide SA6 had a minimum inhibitory concentration (MIC) of 15.6 mu g/mL against Staphylococcus aureus. The mean particle size of SPI-SA6 particles (417.4 nm) was significantly smaller compared with soybean isolate protein (SPI) (463.3 nm). Moreover, the polydispersity index (PDI) decreased with increasing peptide concentration, while the particles were stabilized by hydrogen bonding. SPI-SA6 Pickering emulsions were stable for the entire storage period (7 d) and had lower creaming index and droplet size compared with SPI Pickering emulsions. Further, SPI-SA6 Pickering emulsion could effectively inhibit bacterial growth and disrupt bacterial cell membrane structure, to significantly decrease bacteria (S. aureus) numbers to 2.83 CFU/mL during storage and therefore extending the inhibition time. Collectively, peptide SA6 could stabilize Pickering emulsion while exerting antibacterial effects.