泡菜乳酸菌发酵蔬菜汁的研究

对从泡菜中分离出的三株乳酸菌H-1,G-1,X-1,选择了其最适扩大培养基,研究了乳酸发酵蔬菜汁生产中的添加剂对三株乳酸菌生长的影响,并对乳酸发酵蔬菜汁工艺进行了优选。      

泡菜乳酸菌发酵蔬菜汁研究

该文对从泡菜中分离出的三株乳酸菌H-1,G-1，X-1，选择了其最适扩大培养基，研究了乳酸发酵蔬菜汁生产中的矩味剂、酸味剂、抗氧化剂、稳定剂对不同株乳酸菌生长的影响，并对乳酸发酵蔬菜汁工艺进行了优选。     

乳酸菌发酵蔬菜汁的研究进展

阐述了乳酸菌对发酵蔬菜汁的作用、目前发酵工艺中的一些关键技术及发酵蔬菜汁稳定性和乳酸菌固定化细胞技术的研究进展．     

自然发酵辣椒中乳酸菌的分离及其发酵性能研究

本文简单介绍了从自然发酵辣椒中分离和鉴定优良乳酸菌的方法。从中选育出三株乳酸菌Lact 1和Lact 2，Lact 3，并对这三株菌株的特性进行了研究。结果表明：Lact 1、Lact 2和Lact 3这三株乳酸菌在产酸速度、耐盐性等方面都适合用来发酵辣椒。     

果蔬混合汁发酵酸乳的工艺研制

介绍在鲜乳中加入红色蔬菜汁和果汁进行调配,再进行乳酸菌发酵制备果蔬混合汁酸奶的工艺流程。产品既保留果蔬汁的风味,又有乳酸发酵形成的特殊风味,营养价值较高,有一定的保健作用。     

乳酸菌发酵荠菜－番茄复合蔬菜汁的动力学研究

以荠菜和番茄为基料,用嗜酸乳杆菌和植物乳杆菌为试验菌种进行乳酸发酵,在发酵工艺优化的基础上,对5L 罐乳酸菌分批发酵过程进行研究,建立了菌体生长、产物生成和底物消耗动力学模型,经验证,模型的理论值和实验值拟和较好。所建动力学模型对乳酸菌发酵荠菜- 番茄复合蔬菜汁的反应器设计、工艺原理以及有效的控制发酵过程具有指导意义。     

乳酸菌在果蔬及谷物制品中的应用

乳酸菌作为一种益生菌,具有多种生理功能,用其发酵食品更是具有改善风味、延长保质期等特点,因此乳酸菌在各类食品中得到了广泛应用.鉴于乳酸菌在乳制品中的应用历史较为悠久,且有广泛的报导,本文仅列举了近些年乳酸菌较新的应用领域,阐述了其应用现状及益处, 并对今后发展提出了建议.乳酸菌可实现多种果汁、蔬菜汁及谷物制品的发酵,通过乳酸发酵,实现了菠萝皮、麦麸等的利用,改善了原料口味,提高了利用价值。     

黄酒发酵过程中乳酸菌的分离、鉴定及生物学特性研究

为研究乳酸菌在黄酒发酵过程中的作用,从黄酒不同发酵时期的发酵醪液中分离得到三株乳酸菌,并对其进行鉴定和生物学特性研究。结果表明,MJ0301为植物乳杆菌(Lactobacillus plantarum),FH0201和HJ112为希氏乳杆菌(Lactobacillus hilgardii)。在产乳酸方面,MJ0301产乳酸能力最强,速度最快;HJ112次之,FH0201最弱。在耐酸性方面,三株菌在pH2.0的高酸性环境下均不能生存;在pH2.5的酸性环境下,三株菌虽然能够生存,但活菌数的数量级仅在104CFU/mL;在pH大于3.0的环境下,三株菌生长良好。在耐盐性方面,MJ0301在8%(w/v)的NaCl中依然表现出较强的耐受性,FH0201和HJ112在7%(w/v)的NaCl中虽然活菌数有所下降,但数量级依然在107CFU/mL。三株菌具有的良好产乳酸和耐酸能力对黄酒的顺利发酵起着重要的作用,而良好的耐盐性能为研究其潜在的益生功能奠定了一定的基础。      

乳酸菌Lact.1、Lact.2和Lact.3在发酵碎鲜辣椒中的应用研究

Lact.1、Lact.2和Lact.3是从自然发酵辣椒中选育出的具有广谱、高效抑菌活性和良好发酵性能的三株乳酸菌.用它们对辣椒进行发酵实验,通过正交试验得出:三株乳酸菌用于辣椒发酵时的最佳接种量分别为1%、1%、0.5%,食盐的最佳添加量为10%.测定自然发酵辣椒与接种发酵辣椒的发酵周期和亚硝酸盐的含量,结果表明:自然发酵碎鲜辣椒的发酵周期明显长于接种发酵碎鲜辣椒,亚硝酸盐含量明显高于接种发酵碎鲜辣椒.     

侗族传统发酵酸肉中乳酸菌的筛选、发酵特性及安全性分析

为得到适合肉制品发酵的菌株,本研究采用传统微生物分离方法对侗族传统发酵酸肉中的乳酸菌进行分离鉴定,并对其发酵特性和安全性进行分析。结果表明,从发酵酸肉中分离得到54株乳酸菌,按照肉用发酵剂的基本原则进行筛选后得到S26、S42、S53三株性能优良菌株,结合形态学、生理生化特征和16S rRNA序列分析后确定:S26为香肠乳杆菌(Lactobacillus farciminis),S42为植物乳杆菌(Lactobacillus plantarum),S53为乳酸片球菌(Pediococcus acidilactici);三株菌生长良好且产酸速度快,24 h内可以将pH降到3.5左右;菌株对于氨基糖苷类、青霉素类、头孢类等大多数抗生素无耐药性,且无质粒和溶血现象;并且三株菌之间无拮抗作用,可将三株菌复配后用于肉类的发酵。     

凝结芽孢杆菌中与乳酸生产相关的乳酸脱氢酶基因的研究

对5株凝结芽孢杆菌乳酸生产情况进行研究,并以凝结芽孢杆菌ATCC7050作为乳酸脱氢酶基因研究的对象,确定得出其乳酸生产关键的乳酸脱氢酶基因。结果表明:凝结芽孢杆菌生产的乳酸分两种类型:L型乳酸和D型乳酸,但主要以L型乳酸为主,其光学纯度达到97%以上。在凝结芽孢杆菌ATCC7050基因组中存在的ldhL1、ldhL2和ldhD三种乳酸脱氢酶基因中,ldhL2基因没有检测到转录信号,而ldhD转录水平很低,在生长对数期ldhL1基因的转录水平是ldhD基因转录水平的68倍,这说明ldhL1基因是凝结芽孢杆菌ATCC7050乳酸生产的关键性基因。本研究确定了凝结芽孢杆菌ATCC7050乳酸合成中最主要的乳酸脱氢酶基因,对凝结芽孢杆菌代谢研究和基因改造奠定了基础。     

高产酸乳酸菌的筛选、鉴定和生长特性研究

为了获得高品质的乳酸菌用于工业生产,从本实验室保存的8株乳酸菌中筛选出3株产酸量高、生长良好的乳酸菌,并对筛选出的三株菌进行了分析鉴定和生长特性研究。结果表明,鉴定的3株菌中,菌ST1和菌ST3均为副干酪乳杆菌,菌ST6为鼠李糖乳杆菌。菌株ST1和ST3的最适生长温度为31～37℃,ST6的最适生长温度为37～43℃。菌株ST1的最适初始pH为5～7,菌株ST3和ST6的最适初始pH均为6～7。盐度>14%会对菌株的生长产生明显抑制。      

响应面法优化复合乳酸菌培养条件

将从青贮饲料中自行分离得到的3株优良乳酸菌组成复合乳酸菌,利用响应面分析法对复合乳酸菌的培养条件进行优化,在单因素试验基础上,根据Box-Behnken Design设计试验,并利用Design Expert 8.0.6软件对模型和各因素的显著性及可信性进行分析,优化后的最佳培养条件为：培养温度37 ℃、初始pH值为7.0、接种量（配比为1∶1∶1）4%。在此最佳条件下,获得的乳酸菌菌落数对数值为9.79。     

The effects of conditioning on meat collagen: Part 4-The use of pre-rigor lactic acid injection to accelerate conditioning in bovine meat

Injection of fresh bovine muscle with 0·1 m lactic acid (to a level of 10% of original muscle weight) resulted in a pH decline to a minimum pH of 5·33 at 15°C only 3 h after injection. Untreated muscle reached the same pH after 26 h when held at the same temperature. Fresh, unconditioned meat colour was unaffected by pre-rigor 0·1 m lactic acid injection as assessed by visual inspection. The percentage of perimysial collagen extracted as the soluble form was significantly higher (P < 0·05) from three muscles of varying quality when pre-injected with 0·1 m lactic acid and conditioned from 1 to 14 days, than from conditioned untreated muscles. SDS-polyacrylamide gel electrophoresis of CNBr peptides from insoluble perimysium obtained from three muscles of varying quality revealed no obvious differences due to pre-rigor lactic acid injection before conditioning. However, analysis of the high molecular weight perimysial collagen CNBr peptides from lactic acid treated muscles by two-dimensional SDS-polyacrylamide gel electrophoresis revealed an increased incidence of degradation in this region compared with untreated controls. These data strongly suggest that pre-rigor injection of beef muscle with lactic acid may accelerate conditioning. The implications of this finding are discussed.     

Xylooligosaccharide fermentation with Leuconostoc lactis

Strains of Leuconostoc lactis SHO-47 and Le. lactis SHO-54, producing the clinically useful enzyme NAD-specific 6-phosphoglucanate dehydrogenase, were cultivated with a hydrolyzed birch wood xylan as the unique carbon source to produce D-lactic acid for poly(D-lactic acid). In addition to the strains SHO-47 and SHO-54, Lactococcus lactis IO-1, well known as a good xylose-utilizing lactic acid bacterium, was used as a control to confirm the extent of hemicellulose hydrolysis. The fermentation time for lactic acid of strains SHO-47 and SHO-54 was 12 h, and produced respectively 2.3 and 2.2 g/l lactic acid from 8.5 g/l hydrolyzed xylan, whereas the fermentation time of strain IO-1 was 21 h, and produced 1.3 g/l lactic acid. Xylooligosaccharides from xylobiose to xylohexose were utilized more rapidly than xylose in the cultures of strains SHO-47 and SHO-54. However, xylose concentration increased temporarily and then decreased in the culture of strain IO-1. On the other hand, xylooligosaccharides larger than xyloheptaose were not utilized by these three strains. The xylosidase activities of SHO-47, SHO-54, and IO-1 were induced by xylose or a mixture of xylobiose and xylotriose. The xylosidases of these three strains were localized in their cytoplasm.     

Development of a multiple-step process for the microbial decontamination of beef trim

A multiple-hurdle antimicrobial process for beef trim was developed. The microbial profiles of inoculated lean beef trim tissue (BTL) and fat-covered lean beef trim (BTF) were monitored during prolonged refrigerated storage following the application of successive multiple antimicrobial treatments applied to inoculated beef trim on a processing conveyor belt set at a belt speed of 1 cm/s. Beef trim (meat size approximately 15 by 15 cm) was preinoculated with bovine feces before all treatments that included the following: control, no treatment; water wash at 65 psi for five passes; water plus lactic acid (2% [vol/vol] room temperature lactic acid wash at 30 psi for three passes); combination treatment 1 (water plus 65 degrees C hot water at 30 psi for one pass plus hot air at 510 degrees C for four passes plus lactic acid), combination treatment 2 (water plus hot water at 82 degrees C for one pass plus hot air at 510 degrees C for five passes plus lactic acid), and combination treatment 3 (water plus hot water at 82 degrees C for three passes plus hot air at 510 degrees C for six passes plus lactic acid). The effects of treatments on bacterial populations were monitored by enumerating mesophilic aerobic bacteria (APC), presumptive lactic acid bacteria (PLAB), psychrotrophic bacteria (PCT), coliforms, and Escherichia coli biotype 1 on product stored for up to 7 days at 4 degrees C. In the case of BTL, the numbers of APC, PCT, and PLAB increased during storage at 5 degrees C, whereas the numbers of coliform and E. coli decreased on average by 1.8 log CFU/cm2, then remained constant following the initial reduction. Negligible effects on color quality were observed from multihurdle treatment combination 1. In the case of the BTF, the microbial reductions by treatments were much greater than the reduction on BTL. The pH of treated BTF increased more slowly than the pH of treated BTL, resulting in further reduction of the microflora on BTF. Except for control and water treatments, all sample treatments involving lactic acid resulted in continuously decreasing microbial populations. Based on microbial reduction and quality aspects, it was concluded that successively applied combination antimicrobial treatments for meat trim could offer potential food safety benefits.     

酒曲中乳酸菌的筛选及其在板栗糯米饮料发酵中的应用

为筛选出适合植物基质发酵的优良乳酸菌.本文以米曲为目标乳酸菌的供体,筛选高产酸、耐胃肠环境能力良好的乳酸菌,并评估了乳酸菌的抗氧化活性及其在板栗糯米饮料中的发酵能力.从酒曲中共分离出84株乳酸菌,其中有38株的产酸量≥10 g/L;在进一步的耐酸耐胆盐、模拟胃肠实验中,共筛出3株乳酸菌株;经16S rDNA鉴定这3株乳...     

Bacteriological quality of broiler carcasses as affected by in-plant lactic acid decontamination

In an attempt to improve the bacteriological quality of broiler carcasses the bactericidal effect of treatments with 1% and 2% lactic acid was investigated. Bacterial colonisation was determined immediately after treatment, after the carcasses had been chilled and during storage at 0 degrees C. Examination included numbers of mesophilic aerobic and psychrotrophic aerobic colony-forming units (CFU), CFU of Enterobacteriaceae at 37 degrees C and CFU of Staphylococcus aureus. Immediately after treatment colonisation per gram skin was generally reduced by about 1 log. Initially 2% lactic acid was not found significantly more effective in reducing colony counts than 1%. However, treatment with 2% lactic acid suppressed post-decontamination colonisation with Enterobacteriaceae more effectively than 1% lactic acid, as determined after 15-18 days storage at about 0 degrees C. Lactic acid treatment was most effective when applied shortly before chilling. Successive treatment at three different stages during slaughtering did not increase reduction of colony counts. It is concluded that decontamination with 1-2% lactic acid at pH 2, when applied shortly before chilling, will markedly improve the bacterial safety and increase the refrigerated shelf life of broiler carcasses.     

乳酸对主要发炎和抗炎细胞因子的影响

目的:通过不同给药途径观察及评价了乳酸对小鼠血清中IL-6、IFN-γ、IL-1β、TNF-α、IL-10、IL-4水平的影响,进而研究了乳酸对免疫系统的调节作用。方法:通过灌胃、腹腔注射、尾静脉注射三种途径给小鼠乳酸,分别在给药4、3、3h后取血分离血清,采用ELISA法检测血清中IL-6、IFN-γ、IL-1β、TNF-α、IL-10、IL-4的含量。结果:实验组三种给药途径对小鼠血清中IL-6、IFN-γ、IL-1β、TNF-α、IL-10、IL-4与对照组相比都有显著性变化,给药组小鼠血清中IL-6、IFN-γ、TNF-α、IL-10、IL-4含量明显高于相应的对照组,IL-1β含量显著低于对照组。结论:三种给药途径中腹腔注射的效果最为明显,静脉注射及灌胃组次之。乳酸菌发酵产物的免疫调节作用可能是通过其代谢产物--乳酸发挥作用,乳酸通过对肠粘膜系统细胞细胞因子网络和信号传递系统的调节发挥免疫调节和生理功能。