Orgaongel Nanoemulsion Containing Nisn And D-Limoneneand Its Antimicrobial Activity

Nisin and D-limonene are two natural antimicrobial active substances, which are extracted through biotechnology to extract natural active substance, their antimicrobial properties and non-toxic, have been recognized by the world, followed by World Health Organization has also been approved as a food additive widely used to the food. However, there are limitations. Nisin has a narrow antibacterial spectrum, only actively against gram-possitive bacterium, for gram-negative bacterium and fungi microbes basically no antibacterial effect, Nisin has been widely applied to the actual food as antimicrobial additives such as pasteurized milk, bread, sauces and the like.This research was to develop a novel delivery system containing D-limonene and nisin by food organogel-nanoemulsion and study their effects on the antimicrobial activity. Organogel-nanoemulsions containing with D-limonene and nisin or without nisin were prepared by a homogenization method, which shown good droplet size and stability. Positive effects and outstanding antimicrobial activities of organogel-nanoemulsion containing with D-limonnen and nisin were confirmed by MICs comparison, growth curves of bacteria, scanning electron microscopy and determination of cell constituents’release. Furthermore the organogel-nanoemulsion applied as food preservative in milk also shown excellent antimicrobial performance. Overall, the research described in the current article would be helpful in developing a more effective antimicrobial system for the production and preservation of food, achieved the following main results:1. Organogel-nanoemulsions containing with D-limonene and nisin or without nisin were prepared by a homogenization method, which shown good droplet size and stability. In order to optimize the preparation process, a series of emulsion processes were prepared under different pressures, surfactant-to-oil ratios process times. The results show that when the SOR was 1:6, the pressures was 100mPa and processed 15 times, a 20nm particle size of nanoemulsion can be obtained. Organlgel-nanoemulsion containing D-limonene and nisin exhibited good stable capacity.2. The use of fluorescent labeling method, by measuring the fluorescence microscopy and confocal fluorescence content on organogel-nanoemulsion, the results show the complex organogel-nanoemulsion system with good embedding effect.3. Gradient dilution method was used to determine minimum inhibitory concentration (MIC) of Organogel-nanoemulsions containing with D-limonene and nisin or without nisin. Growth curves of four test strains were determined and investigated that Organogel-nanoemulsion system have a significant influence on the growth condition of bacterium. It shows that, comparing with the addition of pure nisin, organogel-nanoemulsion can inhibit the growth of strains for a long time with a sustained release.4. Scanning electron microscopy for cell structure of three tests showed morphological changes under the organogel-nanoemulsions. Determination of release of cell contents proved the efficient antibacterial and mechanisms of action of antimicrobial organogel-nanoemulsion systems, indicating a proof of the role of the antimicrobial agent for the destruction of the cell membrane.