Nisin/壳聚糖纳米颗粒的制备、表征及其在炼乳中抗李斯特菌研究

Study on preparation,characterization and antibacterial activity of Nisin/Chitosan nanoparticles against L.monocytogenes in condensed milk

乳酸链球菌素(Nisin)作为一种天然、安全、高效的食品添加剂,因其对革兰氏阳性菌的广谱抗菌效果而受到广泛关注。然而Nisin会与食品成分发生键合或酶解反应,降低了稳定性与生物活性,从而限制其在食品中的直接应用。采用静电自组装技术,制备包埋Nisin的壳聚糖纳米颗粒,从而拓展Nisin在食品中的应用。结果表明,当Nisin浓度为5 mg/mL时,Nisin/壳聚糖纳米颗粒的平均粒径为343.4 nm,PDI值为0.233,Zeta电势为45.0 mV,包封率为48.6%,在25℃和4℃储存条件下具有很好的储存稳定性。抗菌实验结果显示,在不影响炼乳品质的前提下,由于Nisin的缓慢释放,Nisin/壳聚糖纳米颗粒对模拟炼乳体系中的李斯特菌具有良好的抗菌效果。所以,Nisin/壳聚糖纳米颗粒在乳制品的抗菌保鲜中具有良好的应用前景。

Nisin is a safe natural food additive and is highly efficient. It received increasing attentions due to its excellent antibacterial effect against a broad spectrum of gram-positive bacteria. However, the stability and bioactivity of Nisin are influenced by other components in foods which impacts its direct application in food systems. In order to solve this problem, Nisin was encapsulated into chitosan nanoparticles by polyelectrolytes self-assembly technique. When Nisin was 5 mg/mL, the average particle size was 343.4 rim, PDI was 0.233, zeta potential was 45.0 mV, and encapsulation efficiency was 48.6%. The favorable storage temperature was 25℃ and 4℃ . The results of antibacterial experiment indicated that Nisin/chitosan nanoparticles exhibited desired antibacterial activity against L. monocytogenes in condensed milk due to its slower release of Nisin, and it had no adversely impact on the quality of condensed milk. In conclusion, Nisin/chitosan nanoparticles have a broad prospect in dairy product preservation.