一种乳链菌肽生物测定方法及其FORTRAN运算程序

报道了一种乳链菌肽生物测定方法，以浅黄微球菌为敏感指示菌，该法的适用范围为5～100IU／ml；并建立起一套微机运算程序，简化了数据处理工作，尤其适于大批量实验数据运算。     

乳酸链球菌素在生菜保鲜中的应用

Nisin的抗菌效果可以降低生菜表面一些微小创口被微生物侵染的机会,延长生菜的货架期,使其品质得以提升。通过实验发现当Nisin浓度≥0.04mg/g时,随保鲜剂浓度增加其保鲜效果的提升并不显著,因此可以确定Nisin用于生菜保鲜的最适浓度为0.04mg/g。     

The effect of nisin on L. monocytogenes in Turkish fermented sausages (sucuks)

Turkish fermented sausage (sucuk) is a traditional, well-known meat product in Turkey. The aim of this study was to evaluate the effect of different nisin concentrations on Listeria monocytogenes in experimentally contaminated sucuk. Analyses were performed on at 0, 1, 3, 5, 7, 10, 15, 20, 25 and 30days for L. monocytogenes and other microbiological parameters (Total mesophilic aerobic bacteria and lactic acid bacteria) and physico-chemical parameters (pH, a(w) and moisture content).The sucuk dough was contaminated with L. monocytogenes ATCC 7644 at a concentration of 10(6)cfu/g, and the dough was divided into six equal groups. Each group was treated separately with different nisin concentrations (0, 5, 10, 25, 50 and 100μg/g). No L. monocytogenes surviving cells were detected in groups which contained 100μg/g and 50μg/g nisin at day 20 and 25, respectively (p<0.001). In conclusion, the inhibition of L. monocytogenes in sucuk increases with the increasing concentrations of nisin.     

The efficacy of nisin can drastically vary when produced in situ in model cheeses

Nisin, a bacteriocin produced by strains of Lactococcus lactis, has a broad inhibitory effect against Gram-positive bacteria. This study investigated the efficacy of nisin Z against Lactobacillus sakei when produced by a nisin-producing strain L. lactis in model cheeses manufactured with ultrafiltrated milk. These cheeses, containing 0, 4 or 10% of gelatin in their dry matter, were inoculated with both strains. Measurement of Lb. sakei loss of viability was an indirect indicator of nisin in situ efficacy. After 24 h, the loss of viability of Lb. sakei was from 0.73 ± 0.14 to 3.30 ± 0.60 log₁₀ cfu g⁻¹ in the cheeses with 0 and 10% of gelatin, respectively, indicating a better in situ efficacy of nisin when gelatin was incorporated. However, the concentration of nisin produced by Lactococcus was similar (3.5 μg g⁻¹) in all model cheeses when measured using an enzyme-linked immune sorbent assay (ELISA). The growth of Lactococcus was slightly improved when gelatin was incorporated, leading to a higher lactate concentration, which is one of the factors explaining the increased nisin efficacy. These results reinforced previous observations that prediction of nisin efficacy in complex food systems remains difficult.     

Nisin及其在食品工业中的应用

乳酸链球菌素(Nisin)是某些乳链球菌产生的一种活性多肽物质,是高效、无毒副作用的天然生物防腐剂,是目前世界上惟一允许使用在食品防腐上的抗菌素。综述乳酸链球菌素的结构、性质、抑菌机理及其在食品工业中的应用研究进展。     

Characterisation of the technological behaviour of mixtures of mesophilic lactic acid bacteria isolated from traditional cheeses made of raw milk without added starters

In this work, the technological behaviour in milk of a set of Lactococcus lactis strains, alone or in combination with strains of Leuconostoc spp. and Lactobacillus spp. isolated from traditional, raw milk cheeses made without commercial starters, was investigated. Small, mixture‐specific differences during milk fermentation were recorded for growth, milk acidification and production of organic acids, volatile compounds, free amino acids and biogenic amines. Four combinations appropriate for use as dairy starters were tested in pilot‐scale cheese trials. Two mixtures produced cheeses of high flavour and taste quality; these could be confidently used as starter cultures.     

基于微囊细胞耦合发酵生产Nisin泡沫分离条件的研究

研究嗜热乳链球菌（Streptococcus thermophilus）6032海藻酸盐-壳聚糖-海藻酸盐（ACA）液芯微囊细胞发酵生产Nisin泡沫分离的影响因素,探索最佳分离条件。在单因素试验的基础上,以Nisin富集比作为评价指标,采用正交试验对泡沫分离Nisin的条件进行优化。结果表明,通气速率和泡沫层高度是影响分离效果的显著因素。为获得较多的Nisin,且不影响发酵,同时兼顾分离效果,确定最佳分离条件为：分离pH值为6,泡沫层高11 cm,通气速率为0.15 L/min,分离时间60 min。在该最佳条件下,Nisin回收率为83.89%,Nisin富集比为8.4,细胞富集比为0.221。     

应用真空软包装配合生物保鲜剂加工莱豆小菜产品工艺优化研究

研究莱豆真空软包装时的杀菌工艺特性,确定可采用常压杀菌的产品的最佳杀菌工艺条件为:100℃,30min.对于需要高压杀菌的产品,则提出真空软包装配合生物保鲜剂的技术,以降低杀菌强度,保持感官品质,并采用正交实验筛选工艺条件,所得结果为:浸泡液Nisin的浓度0.2g/kg,杀菌温度106℃,杀菌时间12min,所生产的产品感官品质优良,大豆异黄酮保存率80%以上,产品理化和卫生指标符合食品卫生标准,保质期一年.     

分割托盘小包装冷却肉溶菌酶、Nisin、GNa液保鲜试验研究

在溶菌酶、Nisin、GNa保鲜剂对托盘小包装冷却肉复合性保鲜的基础上,为取得更好的保鲜实验效果,进一步开展了溶菌酶、Nisin、GNa保鲜剂正交实验研究,以研究出能应用于生产实际的托盘包装冷却肉的有效保鲜剂。通过L9(34)正交试验,结果表明,三种保鲜剂经正交实验配合使用,对非真空托盘包装保鲜冷却肉的保鲜效果非常显著,使托盘包装保鲜的冷却肉在0～4℃条件下,有效保存时间达到24天以上。经正交实验研究后得出较优的工艺条件为A3B2C2D2,即GNa液采用5000ppm,Nisin2500ppm,溶菌酶2500ppm,用乳酸调pH值至4.5。     

冷却肉天然复合保鲜剂配比的优化

根据中心复合设计原理,在琼脂扩散法得出3 种天然保鲜剂最小抑菌浓度基础上,运用Minitab14 数据统计分析软件,采用四因素二水平中心复合响应曲面分析法,确定保鲜剂的最佳配比为Nisin 0.2773g/100mL、溶菌酶0.46g/100mL、乳铁蛋白0.604g/100mL、pH5.16。pH 值与乳铁蛋白、pH 值与溶菌酶、pH 值与Nisin、乳铁蛋白与溶菌酶以及溶菌酶与Nisin 之间均存在显著的交互作用(P＜ 0.01),而乳铁蛋白与Nisin 交互作用不显著(P＞0.05)。单因素对细菌总数影响的大小次序为Nisin ＞溶菌酶＞ pH 值＞乳铁蛋白。