新疆风干肉中优势乳酸菌的分离及产酶特性分析

利用可培养方法,对新疆风干肉中乳酸菌进行分离筛选,结合生理生化和16S r RNA序列对其鉴定,并分析其在不同温度下的产酶特性。结果显示,菌株t L-4为植物乳杆菌(Lactobacillus plantarum);t L-7为棒状乳杆菌(Lactobacillus coryniformis),而菌株a L-16为戊糖乳杆菌(Lactobacillus pentosus)。3株菌的乳酸脱氢酶活性都较高,相比而言,t L-4和a L-16比t L-7有较高活性,分别为112.86 U/m L和94.62 U/m L。a L-16的亚硝酸盐还原酶活力最高,为14.72 U/m L,t L-7的亚硝酸盐还原酶活力较低,为4.63 U/m L。菌株t L-7的酯酶活力较高为13.25 U/m L,t L-4的酯酶活力为11.45 U/m L,而a L-16的酯酶活力相对较低为9.67 U/m L。3株乳酸菌在不同温度下的产酶特性也不同,且菌株间的最适产酶温度存在差异,3株菌在30~40℃产酶能力强,超出这个温度范围,产酶能力下降。     

纯种乳酸菌接种发酵辣椒综合品质特性研究

为了获得高产γ-氨基丁酸（GABA）且综合性能优良的乳酸菌,以10株乳酸菌作为出发菌株对发酵辣椒进行纯种接种发酵,采用逼近理想解排序（TOPSIS）法分别从发酵产酸、抑菌性、亚硝酸盐积累以及生成γ-氨基丁酸能力等方面进行多因素综合评价。结果表明,发酵乳杆菌与食果糖乳杆菌的产酸速度较好,最终产酸量分别为0.020 8 g/100 g、0.020 3 g/100 g;乳链球菌和戊糖乳杆菌对大肠杆菌和金黄色葡萄球菌的抑菌作用最明显,其抑菌圈直径d=11 mm;乳酸片球菌产亚硝酸盐能力最弱,最终含量为1.7 mg/kg;食果糖乳杆菌与乳酸片球菌产GABA能力强,分别为1.97 mmol/L、1.86 mmol/L。采用TOPSIS法对10株菌种进行多因素综合评价,最终得到发酵乳杆菌与食果糖乳杆菌为综合品质特性较好的发酵优良菌株。     

湖南剁辣椒降解亚硝酸盐乳酸菌筛选鉴定及发酵特性研究

为筛选出湖南地区剁辣椒中具有高效降解亚硝酸盐的乳酸菌,从湖南省4个市采集的12个样品中共分离出33株乳酸菌。将分离出的乳酸菌在含有250 mg/L亚硝酸盐的MRS培养基中培养24 h,选取降解亚硝酸盐能力较强的乳酸菌,进行16S rDNA分子生物学鉴定,并测定其发酵特性。实验中选育了4株具有较强降解亚硝酸盐能力的乳酸菌,分别为短乳杆菌、德氏乳杆菌、植物乳杆菌以及戊糖乳杆菌,其中德氏乳杆菌降解亚硝酸盐的能力最强,MRS培养基中生长24 h,其亚硝酸盐降解率为87.7%,发酵罐恒定pH值6.0,培养24 h,其降解率为98.9%。德氏乳杆菌具有良好的耐酸、耐盐与快速产酸能力,可作为果蔬发酵剂进一步开发利用。     

贵州酸肉中具有高亚硝酸盐降解和耐受能力乳酸菌的筛选与鉴定

从贵州自然发酵的酸肉中分离出19株乳酸菌,选择在MRS培养基中培养24 h的降亚硝酸盐能力最强的3株乳酸菌,经16S r DNA分子鉴定为植物乳杆菌CMRC 3、戊糖片球菌CMRC 7和植物乳杆菌CMRC 19。在模拟肉类发酵的条件下,研究其降解、耐受亚硝酸盐和硝酸盐的能力。3株乳酸菌都具有较好的亚硝酸盐降解能力,发酵120 h后分别降解了65.7%~86.3%的亚硝酸盐;然而它们的硝酸盐降解能力都不显著。CMRC 7和CMRC 19耐受亚硝酸盐的性能最强,最高活菌数分别为8.20lg(CFU/m L)和8.11lg(CFU/m L);这3株菌都具有较好的硝酸盐耐受性,最高活菌数分别为8.21,7.93lg(CFU/m L)和8.20lg(CFU/m L)。试验结果表明,从酸肉中筛选出的这3株乳酸菌都有较强的亚硝酸盐降解能力,同时也有较好的硝酸盐和亚硝酸盐耐受性能,可开发成肉类专用发酵剂。     

酸驼乳发酵乳酸菌菌株的筛选及其发酵特性研究

对新疆自然发酵骆驼乳中乳酸菌菌群进行分离鉴定得到五株乳酸菌,其中乳杆菌3株分别为瑞士乳杆菌(Lactobacillus helveticus)、植物乳杆菌(Lactobacillus plantrum)和开菲尔乳杆菌(Lactobacillus kefiri),片球菌2株分别为乳酸片球菌(Pediococcus acidilactici)戊糖片球菌(Pediococcus pentosaceus)。分离鉴定出的五株乳酸菌在培养基中生长良好,其活菌数在培养16 h后能达到109 CFU/m L。将传统酸奶发酵剂接种于骆驼乳中并于42℃条件下培养,发现其在骆驼乳中能较好地产酸,其添加量在0.1%时最适。将筛选到的乳酸菌制备成生产发酵剂与传统酸奶发酵剂复配,得到瑞士乳杆菌组的复配效果最佳,具有最优的产酸效果,在经过6 h发酵后p H值降到4.5左右,酸度达到85oT,且制备的发酵骆驼乳具有最好的感官品质,其感官评分明显高于其他菌株复配进行发酵的骆驼乳产品。因此,可将0.1%传统酸奶发酵剂与筛选到的瑞士乳杆菌制备的生产发酵剂复配应用于酸驼乳发酵。     

发酵乳杆菌和戊糖乳杆菌降解亚硝酸盐的效果比较研究

亚硝酸盐是潜在的致癌物质,在各类食品中广泛存在,研究食品中亚硝酸盐的降解对保证食品安全有很重要的意义。乳酸菌是具有多种生理功能的益生菌,对亚硝酸盐有一定的降解作用。在不同接种量、不同培养温度、不同起始pH和不同亚硝酸钠起始浓度条件下分别比较了发酵乳杆菌和戊糖乳杆菌对亚硝酸盐的降解效果。研究表明,发酵乳杆菌在接种量≥1%时,48h就有明显的降解效果;戊糖乳杆菌在接种量≥3%时,48 h才有明显的降解效果。pH值在3.5~5的情况下,2株乳酸菌对亚硝酸盐都有较好的降解效果。发酵乳杆菌在37℃环境下对亚硝酸盐降解效果最好;而戊糖乳杆菌则是在32℃时对亚硝酸盐的降解效果最好。2株乳酸菌对亚硝酸盐最适宜的降解初始浓度≤120μg/mL。结果表明,在相同条件下发酵乳杆菌比戊糖乳杆菌对亚硝酸钠的降解效果好。为发酵食品中优良乳酸菌株的筛选提供科学依据。     

传统乳制品中乳酸菌的分离及性能研究

从内蒙古地区采集的16个传统发酵乳制品中共分离到27株乳酸菌,其中干酪乳杆菌假植物亚种4株,干酪乳杆菌1株,戊糖乳杆菌1株,阿拉伯糖乳杆菌1株,粪肠球菌1株,屎肠球菌2株,乳酸乳球菌乳酸亚种12株,格氏乳球菌2株,野生链球菌3株。分离菌株发酵10%(W/V)脱脂乳的滴定酸度平均为52.3°T,乳杆菌中IML15-1滴定酸度和黏度分别为101.8°T和1307.5mPa·s;乳酸球菌中IMS8-2的黏度达到1567.5mPa·s。     

植物乳杆菌降解亚硝酸盐及其亚硝酸盐还原酶的研究

对一株分离自泡菜的植物乳杆菌进行了亚硝酸盐降解的相关研究。首先研究了培养条件对植物乳杆菌降解亚硝酸盐的影响,结果表明:该菌降解亚硝酸盐的最适培养温度为30℃,最适碳源为葡萄糖,最适氮源为酵母抽提物,而在MRS培养基中降解亚硝酸盐能力最强。随后对该菌的亚硝酸盐还原酶进行了提取纯化和酶学性质研究,结果表明:该植物乳杆菌的亚硝酸盐还原酶可能为细胞色素cdI型,分子量大小约为123.2kDa;其最适反应温度为35℃,最适pH值为6.5,Km值为30.0mmol/L;Cu~(2+)和Mn~(2+)为该酶的激活剂,而Zn~(2+),K~+,EDTA为该酶的抑制剂。     

乳酸菌固态发酵豆粕产酸性能分析

该研究以实验室保藏的优良乳酸菌为研究对象,探究6株乳酸菌液体和固态发酵豆粕产有机酸的变化。结果显示,6株乳酸菌MRS培养基液体发酵和固态发酵豆粕产酸效果均存在较大差异。菌株MRS培养基发酵结果表明,植物乳杆菌（Lactobacillus plantarum）BLCC2-0410、BLCC2-0069总酸含量分别为18.90 g/L、18.25 g/L,显著高于其余4株菌（P＜0.05）。固态发酵豆粕结果表明,使用植物乳杆菌BLCC2-0410发酵后豆粕pH值可下降到4.33,总酸含量最高为33.73 g/kg,乳酸含量为18.91 g/kg,酒石酸含量为10.43 g/kg,柠檬酸含量为3.79 g/kg,明显高于其他菌株,因此,确定发酵豆粕产酸的最适菌株为植物乳杆菌BLCC2-0410。     

不同乳酸菌产谷氨酸脱羧酶特性研究

通过对发酵乳杆菌、植物乳杆菌、短乳杆菌所产谷氨酸脱羧酶(GAD)的酶学性质进行比较,分析酶反应温度、pH值、磷酸吡哆醛(PLP)浓度、酶浓度与酶活性的关系,并对高活性乳酸菌GAD酶的米氏常数进行测定。结果表明,3株乳酸菌GAD酶的最适温度为40℃,最适pH值为4.5,在PLP添加量为0.1mol/L时,对酶的促进作用达到最高,发酵乳杆菌Km值为0.05215mmol/L,最大反应速度Vmax=2.08μmol/min;短乳杆菌Km值为0.0243mmol/L,最大反应速度Vmax=1.01μmol/min。     

发酵风干肠中乳酸菌的发酵性能

对从自然发酵风干肠中分离的6 株乳酸菌的发酵性能进行评价,主要包括测定菌株的生长曲线、产酸能力、对NaCl及NaNO2的耐受能力,同时通过吲哚实验和抗生素敏感性测定对菌株的安全性进行初步评价。结果表明：6 株乳酸菌生长趋势接近,均在8 h左右进入生长稳定期,pH值在0～8 h下降最快,清酒乳杆菌和发酵乳杆菌的产酸能力更强;所有菌株均可在6 g/100 mL NaCl和0.015 g/100 mL NaNO2条件下生长,植物乳杆菌和弯曲乳杆菌的NaCl耐受能力最优,清酒乳杆菌和发酵乳杆菌则对NaNO2具有最强的耐受能力;吲哚实验中6 株乳酸菌的反应结果均为阴性,对实验所选抗生素无耐药性,说明6 株乳酸菌具有较好的发酵性能和安全性,可作为功能性发酵剂用于发酵肉制品的生产。     

Enzyme activities of lactic acid bacteria from a pearl millet fermented gruel (ben-saalga) of functional interest in nutrition

Lactic acid bacteria responsible for the fermentation of a pearl-millet based fermented gruel, ben-saalga, were investigated for enzyme activity in relation with the nutritional characteristics of gruels used as complementary foods for young children. Thirty pre-selected LAB from a set of 155 isolates were characterized principally for their ability to produce amylase, phytase and alpha-galactosidase. Two Lactobacillus plantarum strains (4.4 and 6.1) and three Lactobacillus fermentum strains (11.11.2, 3.7, 7.4) able to produce one or more of these enzymes were selected. Only weak amylase activity was found in the two Lactobacillus plantarum strains. alpha-amylase activity was associated with cells and was lower than 0.05 Ceralpha Units/ml. Phytase activity was detected in all five strains and was linked to the cell. The highest phytase activity was found in Lb. plantarum 4.4 and 6.1 (348.7 +/- 17.4U/ml and 276.3 +/- 51.4U/ml, respectively) and Lb. fermentum 7.4. (276.3 +/- 13.2U/ml). All strains displayed a cell-linked alpha-galactosidase activity. In a medium containing 2% glucose, the highest cellular activity was found in Lb. fermentum 3.7 (1441.1 +/- 133.7U/ml) and Lb. plantarum 4.4 (1223.1 +/- 148.3U/ml) after 6h of fermentation in the presence of stachyose, and in Lb. plantarum 4.4 (763.3 +/- 23.5U/ml) and Lb. fermentum 7.4 (346.7 +/- 14.8U/ml) after 24h of fermentation with raffinose. These results are consistent with previous observations showing that phytates and alpha-galactooligosaccharides decreased during the natural lactic acid fermentation of pearl millet slurries, and that partial starch hydrolysis can be performed by endogenous microflora provided a pre-gelatinisation step is included in the process.     

眉山泡菜中乳酸菌的分离鉴定

目的：分析眉山泡菜的基本数据和乳酸菌的菌种构成。方法：从眉山市采集泡菜12 份,测定pH值、总酸度、盐度、乳酸菌计数,用16S rRNA序列分析法鉴定菌种。结果：样品pH值的范围是3.37～3.89,总酸度的范围是0.65～0.92 g/100 g（以乳酸计）,盐度的范围是4.16%～5.28%（以NaCl计）,MRS和M17乳酸菌计数分别是1.71～6.33、1.33～5.78（lg（CFU/g））。总酸度对乳酸菌计数影响最大。共分离鉴定出16 株乳酸菌：Lactobacillus fermentum（2 株）、Lactobacillus plantarum（3 株）、Lactobacillus brevis（2 株）、Lactobacillusacidophilus（1 株）、Lactobacillus casei（1 株）、Lactobacillus pentosus（1 株）、Lactobacillus delbrueckii（1 株）、Lactococcus lactis（3 株）、Pediococcus pentosaceus（2 株）。结论：眉山泡菜中乳酸菌存在多样性,实验结果为工业发酵生产泡菜积累了菌株。     

蔬菜发酵菌种的筛选及发酵特性

为了选择适合蔬菜发酵的发酵菌种,本研究从四川泡菜老汤中分离的6 种乳酸菌Lactobacillus plantarum、Lactobacillus fermentum、Lactobacillus brevi、Lactobacillus pentosus、Leuconostoc mesenteroides、Lactobacillus lactics筛选发酵菌种。6 种乳酸菌接入亚硝酸盐的MRS培养液中,6 种乳酸菌还原亚硝酸盐的大小顺序为Lactobacilluspentosus＞Lactobacillus plantarum＞Leuconostoc mesenteroides＞Lactobacillus fermentum＞Lactobacillus lactics＞Lactobacillus brevis。以pH值降低的速率为发酵速率,Lactobacillus plantarum、Lactobacillus pentosus、Leuconostocmesenteroides这3 种发酵剂的发酵速率较其他3 种快,并且通过乳酸菌的全细胞蛋白电泳实验得出此3 种乳酸菌在甘蓝发酵过程中能够成为优势菌。从乳酸菌还原亚硝酸盐的能力、发酵速率、发酵菌种的生存能力（是否能成为优势菌）的实验结果表明Lactobacillus plantarum、Lactobacillus pentosus、Leuconostoc mesenteroides这3 种乳酸菌作为蔬菜发酵的发酵剂。通过对3 种发酵菌种发酵特性的研究可知,Leuconostoc mesenteroides较另两种生长周期短,稳定期维持时间短,很快进入衰退期。Lactobacillus plantarum菌较Lactobacillus pentosus、Leuconostoc mesenteroides耐酸,Leuconostoc mesenteroides对酸敏感。Leuconostoc mesenteroides最适生长温度为30 ℃,Lactobacillus plantarum、Lactobacillus plantarum两种菌的最适生长温度是37 ℃。15 ℃条件下Leuconostoc mesenteroides的光密度（OD600 nm）值很低,说明Leuconostoc mesenteroides较Lactobacillus plantarum、Lactobacillus pentosus对低温敏感。     

Selection and Use of Phytate-Degrading LAB to Improve Cereal-Based Products by Mineral Solubilization During Dough Fermentation

ABSTRACT:  New producers of phytate-degrading enzymes, especially lactic acid bacteria (LAB), were used to improve mineral solubilization during dough fermentation. In all, among strains from different sources by microorganisms (150 lactic acid bacteria, 36 yeasts), 38 (24%) exhibited a clear zone around the colonies by hydrolyzing hexacalcium phytate contained in solid medium. When phytase-positive strains from plate assay were tested for phytase activity in liquid medium, 6 of the strains (37%) exhibited phytate-degrading activity in at least one of the 3 different media used. Of the LAB, the highest phytase values were found for  Enterococcus faecium  A86 (0.74 U/mL) and  Lactobacillus plantarum  H5 (0.71 U/mL). Two different starter cultures obtained by combinations of phytase-positive (phy+:  L. plantarum  H5 and L3,  Leuconostoc gelidum  A16, and  E. faecium  A86) or phytase-negative (phy−:  L. gelidum  LM249,  L. plantarum  H19, and  L. plantarum  L8) selected LAB strains, were used to measure mineral concentrations of iron, zinc, and manganese during dough fermentation. Although the 2 kinds of starter showed similar acidic values, the presence of phytate-degrading LAB strains increased mineral solubilization in comparison to the starter phy−.     

降亚硝酸盐乳酸菌的鉴定及生长特性的研究

从传统发酵食品中分离乳酸菌,筛选鉴定降解亚硝酸盐能力较强的菌株,并研究其在白菜汁培养基中的生长及产酸情况,为制作泡菜发酵剂储备优良菌株。结果分离了144株乳酸菌,并获得5株亚硝酸盐降解率在99%以上的菌株,经鉴定菌株Mao21.1和Mao6.2为戊糖乳杆菌,Wang3.1和Mao20.1为植物乳杆菌,Lin2.4为戊糖片球菌。5株菌在白菜汁培养基中生长4h后,各菌株培养液的pH均快速下降;培养20h后,除菌株Mao21.1外,其他菌株培养液pH均降到3.5以下;对数生长末期菌株Mao6.2和Lin2.4活菌数达到108cfu/mL,该两株菌可作为制作泡菜发酵剂的储备菌株。     

Biochemical characterization of lactic acid bacteria isolated from spontaneous fermentation of 'Almagro' eggplants

A total of 149 strains of lactic acid bacteria isolated from the spontaneous fermentation of 'Almagro' eggplants were characterized and identified. Of the isolates, 148 were determined as belonging to the genus Lactobacillus. A coccoid, gram-positive database-negative isolate was obtained in the early stages of fermentation. The Lactobacillus strains were divided into six groups based on sugar fermentation patterns and other physiological and morphological characteristics, and were identified as Lactobacillus plantarum biotype 1 (54.4%), Lactobacillus brevis biotype 2 (19.5%), Lactobacillus fermentum (9.4%), Lactobacillus brevis biotype 3 (5.4%), Lactobacillus pentosus (4.7%) and nine strains, which were not included in the previous species, were grouped as Lactobacillus spp. (6.0%). Fermentation was initiated by Lactobacillus brevis biotype 2 and Lactobacillus fermentum. During the fermentation Lactobacillus plantarum became the predominant species.     

四川泡菜中产γ-氨基丁酸微生物的系统发育与表达能力评估

为拓展产γ-氨基丁酸(γ-aminobutyric,GABA)微生物资源,以四川泡菜为分离源,从中分离产GABA的乳酸菌和酵母,并对其GABA表达能力进行评估。通过分离纯化,从四川泡菜中获得了338株乳酸菌和67株酵母。采用纸色谱测定,筛选获得12株乳酸菌和3株酵母菌具有产GABA的能力。生理生化和系统发育研究揭示12株乳酸菌分别被鉴定为Lactobacillus acidophilus(占比8.3%)、Lactobacillus fermentum(8.3%)、Lactobacillus kimchii(8.3%)、Lactobacillus suebicus(8.3%)、Lactobacillus brevis(16.7%)、Lactobacillus parafarraginis(8.3%)、Lactobacillus similis(8.3%)、Lactobacillus plantarum(25.2%)和Lactobacillus pentosus(8.3%);3株酵母中,2株被鉴定为Saccharomyces cerevisiae;1株被鉴定为Candida tanzawaensis。进一步采用高效液相色谱对菌株GABA的表达能力评估发现,乳酸菌Lactobacillus plantarum BC114和Lactobacillus brevis BC237发酵产GABA的能力较强,分别达1 720 mg/L和1 080 mg/L;酵母菌Saccharomyces cerevisiae JM037发酵产GABA的能力较强,达670 mg/L。     

新疆酸奶中高产蛋白酶与产脂肪酶乳酸菌的筛选

从新疆传统酸奶中,利用透明圈法筛选出一株高产蛋白酶的乳酸菌RA3,其蛋白酶活力为38.87 U/mL;利用铜皂法筛选出产脂肪酶的乳酸菌菌株RC4,其酶活力为8.54 U/mL。经API 50CHL生理生化实验和16S rRNA序列比对鉴定RA3为发酵乳杆菌,RC4为植物乳杆菌,为我国发酵食品提供了新的乳酸菌资源。