摘要
【目的】为保证超高压中性食品的杀菌强度,可以通过添加Nisin等细菌素协同杀菌以达到商业无菌要求。本文从分子水平和超微结构揭示二者协同作用下的细胞致死机理,为超高压杀菌在中性食品中的应用奠定理论基础。【方法】采用pH7.0的环境体系,100-500MPa的超高压处理,Nisin浓度为200IU/mL。通过荧光染色法和紫外吸收法检测细胞膜通透性,傅里叶转换红外光谱法检测细菌细胞壁、蛋白以及核酸的变化,透射电镜观察细菌在协同作用下的形态变化。【结果】结果发现:中性条件下,超高压与Nisin协同杀菌作用超过2.5个对数值,协同作用使细菌细胞膜通透性增加了10%-60%;同时使细菌细胞膜的磷脂由液晶态向凝胶态转变,降低了细胞膜的流动性。蛋白质二级结构发生变化,导致蛋白变性。协同作用还破坏了细胞的正常生理形态,致使细胞内容物流出。【结论】结果证实,Nisin是超高压制备中性食品的优良辅助杀菌剂,能够起到有效的协同杀菌作用。
[Objective]High hydrostatic pressure (HHP) could be synergized with Nisin in neutral food system to achieve commercial sterilization.The mechanism of synergistic inactivation by HHP treatment and Nisin was investigated at molecular level alongside ultramicroscopic structure.[Methods]Bacillus subtilis strain was subjected to HHP (100-500 MPa for 15 min) alone and in combination with Nisin (200 IU /mL) in PBS (pH 7.0).Membrane permeability was studied by fluorescent dye and ultraviolet absorption.Membrane lipid,protein and DNA changes were detected by Fourier Transform Infrared.Transmission Electron Microscope (TEM) was used to detect the morphological changes.[Results]In neutral food system,the combined effect of HHP and Nisin reduced the population of the bacteria by 2.5 log,while at the same time increasing the membrane permeability by 10%-60%.The physical state of membrane phospholipid molecules changed from liquid crystalline to gel state with a decrease in membrane fluidity.Treatments at elevated pressures were observed to cause protein denaturalization.Results from TEM demonstrate that cell content leaked owing to the synergistic effect.[Conclusion]This confirms that Nisin is an effective bactericide when combined with HHP in neutral food and that the two inactivation methods have a synergistic effect.
出处
《微生物学报》
CAS
CSCD
北大核心
2011年第1期35-42,共8页
Acta Microbiologica Sinica
基金
教育部新世纪优秀人才计划(NCET-09-0436)~~
关键词
超高压
乳酸链球菌素
协同杀菌
细胞膜通透性
超微结构
high hydrostatic pressure
nisin
synergistic inactivation
membrane permeability
ultramicroscopic structure