复合防腐剂对几种常见畜禽鱼肉的防腐效果研究

乳酸链球菌素（Nisin）、山梨酸钾、双乙酸钠和乳酸钠是常用的食品防腐剂。本文对乳酸链球菌素、山梨酸钾、双乙酸钠和乳酸钠进行复配,并对各单体防腐剂和组成的复配型防腐剂应用于常见新鲜肉类的抑菌效果进行了研究。确定防腐效果最佳的复合防腐剂配方后,通过测定各单体防腐剂和最佳配方复配型防腐剂对常见肉类中菌落总数和挥发性盐基氮的抑制效果,评价其防腐效果。结果显示,与各单体防腐剂相比较,该最佳配方复配型防腐剂能够较明显减缓常见新鲜肉类猪肉、牛肉、鸡肉和鱼肉中菌落总数和挥发性盐基氮的增长,延长新鲜肉类的保质期。     

石香薷挥发油与几种常用食品保鲜剂对冷切肉保鲜效果的研究

本文研究比较了石香薷挥发油与常用防腐保鲜剂Nisin、山梨酸钾、茶多酚在冷切肉冷藏(00C～40C)过程中的保鲜效果。试验结果表明石香薷挥发油具有较好的综合保鲜效果,与其他保鲜剂相比,在抑制细菌生长、减缓TVB-N的升高、保持蛋白质含量稳定等方面有着显著的效果,与对照组相比,能将冷切肉的保鲜期延长7d。     

生鲜调理宫保鸡丁保鲜的配方优化

以乳酸链球菌素(Nisin)、脱氢乙酸钠、山梨酸钾为保鲜剂应用于生鲜调理宫保鸡丁的保鲜,以鸡胸肉为原料,并配以其他辅料,通过正交试验设计,对配比成分的比例进行优化,并对结果进行验证分析.结果表明:0.3g/kg Nisin+0.4g/kg脱氢乙酸钠+0.06g/kg山梨酸钾进行复配时,对生鲜调理宫保鸡丁的保鲜效果最好.用此保鲜剂处理再结合真空包装能使生鲜调理宫保鸡丁在0~4℃条件下保鲜15d以上.     

冷却猪肉中复合保鲜剂配比优化研究

按照五因子二次旋转正交组合设计方案,确定了Nisin、纳他霉素、溶菌酶、茶多酚和壳聚糖复合保鲜冷却猪肉的交互作用,获得最佳配比。结果表明:5种保鲜剂的抑菌效果依次为溶菌酶>壳聚糖>茶多酚>Nisin>纳他霉素;溶菌酶与Nisin、溶菌酶与壳聚糖间存在显著交互效应(P<0.05);浸泡用复合保鲜剂的最佳配比为Nisin0.10%、纳他霉素0.13%、溶菌酶0.20%、茶多酚1.8%、壳聚糖1.8%。     

滚揉腌制液中添加Nisin对川香鸡柳的保鲜效果

在川香鸡柳滚揉腌制液中添加不同含量的Nisin(0.1、0.2、0.3、0.4g/kg,按鸡小胸质量计),结合托盘包装技术对其进行保鲜研究。通过测定其在(4.0±0.5)℃条件下贮藏期间的菌落总数、水分活度、pH值、色差值、贮藏损失各项指标,分析Nisin对川香鸡柳的保鲜效果。结果表明:滚揉腌制液中添加Nisin能显著抑制川香鸡柳中菌落总数的增长(P<0.05),贮藏第8天时最明显,与对照组相比,处理组菌落总数可降低3.32 lg(CFU/g);Nisin可显著提高川香鸡柳贮藏后期色泽亮度和黄度;显著延缓第8天后pH值的升高(P<0.05);但对水分活度影响不显著。综合各因素,添加0.3g/kg Nisin保鲜效果最佳。在滚揉腌制液中添加Nisin对川香鸡柳具有良好的保鲜效果。     

溶氧(DO)对混菌发酵生产Nisin影响的研究

Nisin(乳酸链球菌素)是由乳酸菌产生的一种抑菌活性肽。其在生产过程中需要控制发酵体系的pH,以避免由于乳酸菌代谢积累的乳酸导致pH迅速降低抑制菌体生长。本文采用以能够代谢消耗乳酸的酵母菌为辅助发酵菌的新型混菌发酵方法,在小试条件下研究了在混菌发酵过程中对菌体特别是酵母菌代谢有显著影响的因素溶氧(DO)对混菌发酵生产过程中发酵体系的pH与乳酸含量的变化nisin产量的影响。结果表明,不同水平溶氧对混菌发酵体系中两种菌的生长及代谢产物生成有一定影响。DO 10%与DO 30%时的nisin效价的水平波动范围为24.35%;在分阶段控制发酵体系溶氧水平的条件下获得了较高的nisin效价,效价水平比恒定溶氧提高45.38%。说明分阶段控制发酵体系溶氧水平是较为理想的溶氧控制策略。     

乳酸链球菌素在食品工业中的应用

介绍了乳酸链球菌素(Nisin)的分子结构、稳定性、安全性和抗菌机理的研究进展；综述了乳酸链球菌素在食品工业中的应用现状，并对其应用前景进行展望。     

Interactive inhibition of meat spoilage and pathogenic bacteria by lysozyme,nisin and EDTA in the presence of nitrite and sodium chloride at 24 degrees C

To develop a nisin- and lysozyme-based antimicrobial treatment for use with processed ham and bologna, in vitro experiments were conducted to determine whether inhibition enhancing interactions occur between the antimicrobials lysozyme, chrisin (a commercial nisin preparation), EDTA, NaCl and NaNO₂. Inhibitory interactions were observed between a number of agents when used against specific pathogenic and spoilage bacteria. The observed interactions included lysozyme with EDTA (Enterococcus faecalis and Weissella viridescens), chrisin with EDTA (all Gram-positive organisms), EDTA with NaCl (Escherichia coli, Salmonella enterica serovar Typhimurium, Serratia grimesii), EDTA with nitrite (E. coli, Lactobacillus curvatus, Leuconostoc mesenteroides, Listeria monocytogenes, S. Typhimurium), chrisin with nitrite (Lc. mesenteroides, L. monocytogenes), and NaCl with nitrite (S. Typhimurium, Shewanella putrefaciens). Previous reports have described interactions between nisin with EDTA that resulted in enhanced antimicrobial effect against Gram-negative bacteria, or lysozyme with nisin against Gram-positive bacteria. These interactions were not observed in these experiments. We observed that unlike previous studies, these experiments were conducted on growing cells in nutrient broth, rather than under conditions of nutrient limitation. We propose that screening of antimicrobials for use in food systems in nutrient-deficient systems is inappropriate and that new protocols should be developed.     

Development of spoilage microbiota in beef stored in nisin activated packaging

The aim of this study was to assess the microbial populations causing the spoilage of chilled beef during storage and to evaluate the effect of the use of an antimicrobial packaging for the meat storage. A nisin activated antimicrobial packaging was developed by using a nisin, HCL and EDTA solution and used for the storage of beef cuts at 1 °C. The common spoilage related microbial groups were monitored during the storage of beef in activated and non activated plastic bags by using selective media. The use of the antimicrobial packaging caused an overall significant reduction of viable counts of Gram positive bacteria such as carnobacteria, lactic acid bacteria and Brochotrix thermosphacta whose development was inhibited for at least 11 days of storage compared to the control. Moreover, a 1–3 log cycles reduction of enterobacteria was also registered between 22 and 32 days of storage. The microbiota was assessed at species level by using Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis of 16S rRNA gene of DNA extracted directly from meat and from bulk cells from selective media plates and showed that the species occurring within the targeted microbial groups did not change according to storage conditions. In conclusion, the use of the nisin activated packaging reduced the number of spoilage populations but did not affect the species diversity. Improved antimicrobial packaging is needed, possibly coupled with vacuum storage, to possibly achieve a simultaneous inhibition of more spoilage microbial groups and to preserve the microbiological quality of beef during chilled storage.     

Effect of exopolysaccharides (EPSs) produced by Lactobacillus delbrueckii subsp. bulgaricus strains to bacteriophage and nisin sensitivity of the bacteria

Lactobacillus strains used in this study were isolated from village-type yogurt and raw milk. The isolates were identified as Lactobacillus delbrueckii subsp. bulgaricus by 16 s rDNA sequence analysis and API 50 CHL identification systems. The exopolysaccharide (EPS) production of the strains growth in skim milk were investigated. In addition sensitivity and insensitivity of these strains against domestic bacteriophages and nisin were examined. It was deduced that those strains which had relatively high EPS-producing capacity were insensitive against phages and nisin. Linear relationships were determined between EPS production of the bacteria and bacteriophage and nisin insensitivity of the bacteria.There was a negative correlation between EPS production quantity and phage and nisin sensitivity of the bacteria. Of all the strains, L. delbrueckii subsp bulgaricus B3 produced the highest EPS quantity, and it was insensitive against phages and nisin. Based on these results, it is suggested that L. delbrueckii subsp bulgaricus B3 can be used with the starter culture in dairy industry for stable and high-quality yogurt production.