Nisin复合微粒的制备及其抗菌稳定性的研究

Studies on Preparation of Nisin Complex Particles and Antibacterial Stability

乳酸链球菌素(Nisin)在应用中生物活性受到许多化学和物理因素的影响,采用壳聚糖(CS)/果胶(PE)复合凝聚物对Nisin进行包埋,研究反应的条件及复合微粒的形态结构,并考察包封Nisin经高温和胰蛋白酶处理后的抗菌稳定性。试验结果表明:在pH 6、CS/PE质量比0.6、Nisin浓度1.5%时,Nisin包封率为87.3%,果胶的羧酸和壳聚糖的氨基通过静电相互作用,包封Nisin的颗粒基本成球形,大小约在100 nm^800 nm之间。经120℃处理20 min后,包封Nisin抗菌率是游离Nisin的4倍。当胰蛋白酶与Nisin反应10 min后,游离的Nisin抗菌率只有5%,而包封Nisin抗菌率仍有73%,反应60 min后,抗菌率还有29%,说明CS/PE壁材对Nisin的抗菌性起到很大的保护作用。

The biological activities of Nisin are affected by many chemical and physical factors. Nisin was en- capsulated in the complex of chitosan （CS） and pectin （PE）. The reaction conditions, structure and morphology of the complex were studied. The antibacterial stabilities of encapsulated Nisin were measured after high tem- perature and trypsin treatment. The results showed that the encapsulation effect of Nisin was 87.3 % in pH6 with 0.6 of the CS/PE ratio and 1.5 % of Nisin concentration. Carboxyl groups on pectin and amino groups on chitosan react by electrostatic interactions and particle sizes of NisirdCS/PE complex range from 100 nm to 800 nm with spherical shape. The antibacterial rate of the encapsulated Nisin was four times that of free Nisin after treat- ment for 20 min at 120 ℃. After reaction with trypsin for 10 rain, the antibacterial rate of free Nisin only left 5 %, while that of encapsulated Nisin was 73 %, and remained 29 % after 60 min. The results demonstrated that wall material CS/PE had great protective effect on the antibacterial rate of encapsulated Nisin.